The principles of B2B outreach haven't changed since the early 2000s, but as stricter spam policies, marketing fatigue, and algorithms topple the B2B buying landscape, agencies that fail to experiment and adapt how they connect with buyers will fall behind.
Callbox has built an infrastructure powerhouse for the B2B buying journey, optimizing its databases and proprietary technology. But is it enough if strategic thinking takes a backseat?
Client reviews show its struggles with market nuances, pivots to new approaches, and adaptations outside of scripts — particularly in industries with complex technical offerings.
The ideal agency acts as a business sparring partner. It identifies blind spots and nudges you outside your comfort zone through market shifts. It doesn't settle for the status quo.
While we at Belkins have respect for Callbox, the modern B2B landscape demands more than operational efficiency. It needs strategic experimentation.
In this guide, we explain everything you need to know about Callbox and the repercussions of a limited experimentation culture. We also offer alternatives to consider.
Belkins is one of the top market leaders in lead generation according to the Clutch Leaders Matrix. Since 2017, the elite team at Belkins has experimented with bold approaches and delivered up to 400 appointments for 1,000+ companies annually. to get started.
❗ Disclaimer: This review is based on our industry knowledge, research, and conversations with prospects.
Pricing and ROI
Callbox offers flexible subscription-based pricing starting from $15,000. Many companies are satisfied with the ROI and praise the agency's ability to drive leads. However, several felt that it falls short in its experimentation culture, especially in non-mainstream markets.
Here's a deeper look.
How much does Callbox cost?
Callbox costs $15,000 to $30,000 for a Campaign Pod covering one region or language.
If you're targeting multiple regions or languages, you need more than one Campaign Pod.
For example, if you're entering the North American, UK, and Asia-Pacific markets, expect to invest in three Campaign Pods with an estimated cost of $45,000 to $90,000.
How does Callbox's pricing structure work and what does it include?
Callbox's pricing structure is subscription-based — it doesn't charge hourly or pay-per-appointment rates. A typical package includes outsourced experts, marketing and sales assets, and campaign execution.
The agency offers flexible pricing to align with your sales cycle and pipeline goals. Note the review below where a long-term client successfully negotiated their fee for a guaranteed number of appointments.
Your final pricing depends on your target industry, market reach, and campaign complexity.
Every subscription-based package (or Campaign Pod) includes:
A dedicated team of managers, SDRs, research and data analysts, and digital marketers
Prospecting and ideal customer profile (ICP) development
Targeted buyer content generated by AI (e.g., email templates, web copy)
Callbox's proprietary Smart Engage platform with CRM integration
Multichannel execution (email, phone, LinkedIn, and web retargeting)
Ongoing campaign optimization based on AI-driven analytics, feedback, and business requirements
📌 Belkins tip: Avoid negotiating for lower costs as it means cutting the full-service team — this compromises the quality of service and hurts campaign performance.
Instead, negotiate resource or engagement terms.
At Belkins, when clients request the expertise of our senior specialists, we accommodate them. Our co-founder and chief growth officer, Michael Maximoff, participates in multistep onboarding workshops often.
What's the typical contract length at Callbox?
The typical contract length at Callbox spans from quarterly to annual, according to client reviews.
Is Callbox worth the investment?
Many reviews indicate that Callbox was worth the investment, but several companies thought it was expensive — citing limited insights, struggle with regional nuances, inability to adapt outside of scripts, and lack of strategic pivots in underperforming campaigns.
These recurring issues point to a bigger problem: Callbox’s limited experimentation culture.
Here's what we mean.
Limited insights
While Callbox was receptive to campaign requirements, according to a mid-market client, they wished the agency had provided more detailed insights without having to request them.
Without granular insights, your strategies are guesswork. You won't know what's working in your channels and conversations, let alone what to experiment with in future campaigns.
Every day spent on surface-level insights is another day your competitor partners with a more strategic vendor. Without proactive recommendations, you're second-guessing decisions and losing momentum.
Struggle with regional nuances
Despite the qualified leads, excellent communication, and rapid changes upon request, Callbox couldn't grasp the regional nuances in non-US markets, said a data tech client.
Struggling to decode cultural differences (e.g., using unnatural language or failing to recognize unspoken subtexts) usually points to an issue in market-specific testing.
To adapt in a new region, you need to experiment with messaging variations based on cultural response patterns.
📌 Note: The data tech client also mentioned Callbox's lack of alternative approaches.
In a similar review, an SMB client praised Callbox for securing appointments, but disliked the unnatural cold calls and emails.
Callbox's inability to adapt to the market's language and behavior likely affected its SDRs' communication style, causing unproductive interactions with buyers.
Despite a satisfactory team workflow, Callbox didn't pivot to alternative approaches for underperforming campaigns. The 3-month engagement led nowhere, a mid-sized IT client shared, concluding that Callbox was ineffective for IT-managed services.
When results are poor, experiment with alternative ICPs by expanding the pool of job titles and refining niches.
Your marketing playbook is never one and done. You need to evolve to keep pace with changing market dynamics.
Inability to adapt outside of scripts
In another review, a telecommunications company lamented that Callbox employees needed coaching to talk with prospects on the phone. Considering it was four months into the campaign, this shows the SDRs' inability to improvise based on responses.
Scripts play a crucial role in outreach, but your outsourced SDRs shouldn't use them as a crutch. Over time, they should learn from successful and failed interactions, test alternative conversation paths, and adapt based on responses.
📌 Belkins tip: Ensure your vendor runs multiphase onboarding workshops to learn your brand voice, products, positioning, and sales motion.
This intensive approach gives your outsourced SDRs the foundational knowledge to learn your target audience's goals, challenges, and role in the buying committee. By learning what they care (and worry) about, your outsourced SDRs will know what resonates and how to navigate potential objections in cold calls.
In spite of these recurring issues, most clients are satisfied with Callbox's communication, prompt lead delivery, and proven methodology over 20 years.
Here, a business management consultancy client shared their 15-year partnership. It's a testament to Callbox's track record.
Yet, it raises the question of Callbox's reluctance to experiment. Can it keep up with the turbulent outreach landscape, particularly in complex industries with limited total addressable market (TAM) and stagnated growth?
The average cold email outreach reply rate dropped from 6.8% in 2023 to 5.8% in 2024 alone.
2026 will be another demanding yeardue to tighter spam filters and evolving user behavior.
Callbox's hesitation to pivot from underperforming approaches suggests it may default to familiar playbooks and struggle to navigate ongoing disruptions.
Data sourcing and quality
Callbox gathers data from multiple sources, including third-party providers and its in-house database. It uses Callbox Pipeline, its proprietary lead management platform, to prepare your list.
Here's a deeper look at its data research and profiling.
Which data sources does Callbox use for enrichment?
Callbox uses your ICP, in-house and third-party data, and handpicked research to enrich your lead list. You can submit your own prospect list if preferred.
How does Callbox verify and update contact information?
Callbox verifies and updates contact information through its proprietary software, Callbox Pipeline.
Its tool, DataMiner, extracts information on prospects from over 50 million decision-makers. It removes invalid email addresses and verifies the remaining ones via List Architect.
Validated email addresses are then uploaded to the Smart Calling Engine and Emailer Suite, which SDRs will use to connect with leads.
Callbox qualifies leads based on BANT (Budget, Authority, Need, and Timeline) and demographic and behavioral attributes. Most clients saw a consistent number of leads, but some felt it could've gone deeper in the qualification framework.
How does Callbox ensure lead or appointment quality?
Callbox ensures lead quality by focusing on the BANT framework and demographic and behavioral attributes.
The agency uses its proprietary Smart Calling technology to spot quality leads based on website visits, email replies, and successful phone contacts.
Some clients felt that Callbox should've qualified leads on a deeper level. Below, a regional manager received unsuitable prospects that were counted toward the total engagement.
The ideal vendor continuously refines your lead qualification based on the market landscape, sales team feedback, and meeting outcomes.
💡 Case in point: At Belkins, lead qualification is an ongoing process. When new themes emerge, our SDRs immediately update your qualification logic, ensuring you engage with the most relevant buyers.
For example, if our software client observes a hiring boom in a certain industry that led to an increased technology spend, we refine the qualification logic and prioritize the new segment immediately.
How many appointments can you expect monthly, quarterly, or annually?
Callbox doesn't share the exact number of appointments.
Your appointment count depends on factors like industry, sales cycle, competition, and the buying committee.
For example, while Callbox scheduled 16 appointments for a construction company in the first month, it drove only 1–2 leads per month for a consultancy service.
📌 Belkins tip: Look beyond appointment guarantees in the contract. Instead, check whether the vendor shows a clear timeline for cost optimization.
At Belkins, we outline how your projected cost-per-meeting declines from Year 1 onward (e.g., Year 1: $3,000 per meeting, Year 2: $2,000 per meeting).
How long is the ramp-up period until appointments are set?
Callbox has a relatively short ramp-up period — ultimately, the timeline depends on your industry and campaign complexity. Some clients saw appointments within 1–3 weeks after kickoff, while others saw results in a few months.
Westernacher Consulting, for instance, booked 1–2 weekly meetings after a month of ICP and messaging refinement, product training, and knowledge transfer with the Callbox team.
📌 Belkins tip: Mutual effort drives momentum. Join weekly calls with the vendor to reiterate or pivot your strategy. You'll speed up decision-making, identify bottlenecks, and increase pipeline growth in a shorter time.
Methodology and process transparency
Callbox uses seven channels in its methodology, including email, phone, instant messaging, and live chat. Despite the useful metrics from its lead handoff and reporting processes, several clients wanted comprehensive insights to improve campaign outcomes.
Here's a detailed look.
What specific channels does Callbox use, and how effective are they in my industry?
Callbox uses phone, email, social media, website, instant messaging, HubSpot Live Chat, and events in its multichannel, multitouch marketing framework. Whether they're effective in your industry depends on factors like channel synergy.
💡 Case in point: When Belkins shifted from an email-only to omnichannel strategy (email + LinkedIn + intent calling), our appointment count increased by 30%. Cold email outreach drives higher conversions when aligned with other channels. With consistent messaging, you maximize the impact of each interaction and nurture prospects down the sales funnel.
Using the same lead lists (~1,500 records), we went from booking six appointments per ten prospects (mostly email) to eight out of ten — a 30% lift. Now, it's an omnichannel system: on average, five from email, two from LinkedIn, and one from calling.
How does lead handoff look?
Callbox's lead handoff brief includes a personalized sales introduction copy, the prospect's information, and a recommended multichannel sales cadence to close the deal.
Here's a typical sales sequence. Note how Callbox suggests continuing the conversation with a qualified lead via email, LinkedIn, and phone. It highlights the specific approaches and timeline to follow.
Callbox's reporting process provides custom campaign dashboards of channels covered, touchpoint history on leads, and recommendations to improve the campaigns.
Here's what you'll receive:
Activity status reports (daily, weekly, or monthly on calling, social, and remarketing activity)
Call lists sorted by location and last call
Lead nurturing reports with activity log or email marketing metrics
Live touchpoints (e.g., calls, email opens and replies, website visits)
Mobile streams (e.g., access tasks and notifications across mobile browsers)
Weekly updates on lead status and campaign recommendations via email
Based on reviews, several clients wanted more than standard progress reports with raw data; they wished Callbox had offered comprehensive insights and analysis.
Below, a client shared that the partnership would've been more beneficial had the agency provided more proactive suggestions for better campaign outcomes.
Partner with vendors that have a strong experimentation culture.
The ideal agency explores hypothesis-based strategies early on, actively anticipating market changes instead of reacting to them.
💡 Case in point: Belkins set 77 appointments for Ebco Trends largely due to our culture of experimentation.
We expanded Ebco Trends' ICP and TAM after noticing a high bounce rate in Fortune 1000 companies with sophisticated spam protection.
Our SDRs searched for alternative email addresses and reached out to lower-level managers who are more likely to respond. We also experimented with different messaging, industries, titles, and geographic locations to find the right target audience.
In the end, Belkins saw two deals closed out of the 77 appointments generated, including an old prospect in Ebco Trends' pipeline for 24 months!
Industry experience and team expertise
Callbox assigns a manager, SDR, and marketing experts to each account. These professionals are skilled in broad sectors with diverse needs, not in non-mainstream industries with complex or technical needs.
How is the team structured, and how many people are assigned to my account?
Callbox usually assigns five people to an account: a campaign manager, SDR, an email specialist, a social media expert, and a quality assurance (QA) analyst.
What is Callbox’s experience in specific verticals?
Callbox boasts extensive experience in mass markets rather than narrow industries.
Clients in broad industries highlight the agency's expertise in broad sectors like healthcare and real estate, citing its knack for finding the right decision-makers and driving good conversions.
However, based on reviews, Callbox lacks technical experience in specialized sectors selling complex products. Several clients lament its inability to understand their offerings and adapt outside of scripts.
Selling complex products is a challenge due to a narrow target audience and the need to understand specialized jargon.
The vendor needs to understand the ins and outs of the industry, the product, and unique value proposition (UVP) before launching the first outreach.
💡 Case in point: Belkins conducted extensive research to drive 15 appointments for Smartrek, a wireless connectivity products manufacturer.
Because of the industry's need for meticulous explanation to convey its value, our team spent hours learning the technicalities of water purification and reverse osmosis.
We studied the product descriptions, pricing, and other data, and curated potential objections and responses on a spreadsheet. Our SDRs also experimented with different keywords and titles that speak to the niche product.
In the end, 14 out of the 15 appointments qualified for the client.
Three Callbox alternatives
Add these best lead generation companies to your list if you're seeking alternatives. Here, you'll find a market leader with a strong experimentation culture, one offering pay-per-appointment packages, and another for SMBs.
Belkins
Belkins (that's us 👋🏻) is a lead generation market leader on the Clutch Leaders Matrix. Since 2017, we've delivered up to 400 qualified appointments annually for over 1,000 companies in 50+ industries.
What sets us apart is our:
4th place among the top 1,000 global service providers on Clutch: Work with the only lead generation and sales outsourcing company that ranks on the top 1,000 list worldwide. None of our competitors made the list.
Bespoke full-funnel strategies: Belkins takes a 360-degree approach to client acquisition. Interconnect your channels and touchpoints in a cohesive omnichannel strategy to reach more buyers and stand out from competitors.
End-to-end strategy implementation: Leave the logistics to us, all the way from setup to International Organization for Standardization (ISO) certification and technical compliance. Our elite team of experts diagnose and fix every stage of the deal generation process, boosting your efficiency and productivity.
Rigorous audience profiling: Vet your target buyers from every angle through a multilayered lead research and qualification process. With meticulous insights, you'll improve your odds of connecting with the most relevant buyers today.
Ongoing strategy refinement: Anticipate challenges before they impact growth. Our dedicated team monitors market trends and experiments with bold approaches to deliver a predictable stream of high-fit leads.
In contrast to Callbox, we pride ourselves on our experimentation culture. Our team thinks outside the box to refine your strategy and stay ahead of market disruptions.
Belkins' accelerated pipeline growth for over 1,000 companies in 50+ sectors, especially in niche industries with limited total addressable market (TAM) challenges. Read their success stories.
Revit
Revit supports SMBs and startups through effective outbound with low-commitment terms.
It offers pay-per-appointment packages using cold emails and a fractional SDR department that lets you choose between cold emails, cold calling, or LinkedIn prospecting.
This agency is ideal for scaling your existing business model or building an SDR department.
This agency understands the unique challenges of relying on referrals and inbound channels. If you want to build a profitable outbound function, this agency might be a good fit.
A lead generation agency acts as a sparring partner, not a volume machine
Callbox is one of the largest lead generation agencies. If you want to hit your lead or appointment quota, it’s a great partner to have by your side.
However, reviews highlight its inability to adapt outside of scripts and pivot to alternative approaches.
The B2B landscape is tumbling over spam policies, evolving customer behavior, and unpredictable algorithms.
Operational efficiency may drive results initially, but without a culture of experimentation, it’s only a matter of time before the agency struggles to navigate ongoing market disruptions.
At Belkins, we challenge the status quo. Instead of reacting to market shifts, we proactively anticipate and prepare strategic pivots before challenges impact growth.
For over 8 years, we’ve experimented with unconventional approaches to accelerate pipeline growth, achieving up to 400 appointments annually. Book a call today to get started.
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Priscilla writes topics that lie at the intersection of marketing and sales. She specializes in product-led content, comparison posts, and narrative-led pieces. Her current and past clients include Belkins, Breadcrumbs, DashThis, and Ahrefs.
Expert
Michael Maximoff
Co-founder and Chief Growth Officer at Belkins
Michael is the сo-founder of Belkins, serial entrepreneur, and investor. With a decade of experience in B2B Sales and Marketing, he has a passion for building world-class teams and implementing efficient processes to drive the success of his ventures and clients.
