To,
Enforcement Bureau,
Federal Communications Commission,
Callsto, LLC acknowledges receipt of the Federal Communications Commission’s notice regarding suspected unlawful robocall traffic identified in Cease-and-Desist letter.
Callsto takes its regulatory obligations seriously and is committed to full compliance with 47 U.S.C. § 227, 47 CFR § 64.1200, and its Robocall Mitigation Database certification
Investigation Overview
Upon receipt of the Notice, Callsto, LLC promptly initiated a comprehensive internal investigation into the traffic identified in Attachment A. This investigation included:
- Review of call detail records (CDRs) associated with the identified calls.
- Analysis of signaling and routing data to determine Callsto’s role in the call path.
- Identification of associated customer accounts and downstream providers.
- Evaluation of traffic patterns and calling behavior
Findings
Based on this investigation, Callsto, LLC determined that it did not act as the originating or gateway provider for the identified traffic. Instead, Callsto, LLC functioned as an intermediate provider transmitting traffic received from an upstream provider.
Callsto’s determination is supported by call routing records and network data confirming that the traffic entered Callsto’s network from upstream sources before being transmitted downstream.
Mitigation Actions Taken
Callsto, LLC has taken immediate and decisive action to mitigate the identified traffic:
- Blocked all traffic associated with the identified calling patterns and sources.
- Suspended or terminated the responsible customer account(s), where applicable.
- Prevented further transmission of the identified traffic through our network.
- Initiated enhanced monitoring for similar traffic patterns.
Additionally, Callsto, LLC has taken steps to engage with the downstream provider(s) to notify them of the identified traffic and encourage appropriate remediation measures.
Ongoing Preventative Measures
To prevent recurrence of similar issues, Callsto, LLC has strengthened its robocall mitigation practices, including:
- Enhanced traffic monitoring and anomaly detection systems
- Strengthened Know Your Customer (KYC) and onboarding procedures
- Implementation of stricter traffic vetting and enforcement controls
- Continuous monitoring to identify and block substantially similar traffic
- Third party Media IP blocking tool
- SomosDNO
Callsto, LLC remains committed to ensuring that unlawful robocall traffic does not traverse its network.
Enhanced Robocall Mitigation
Callsto, LLC has implemented enhanced robocall mitigation controls and continuously monitors traceback trends to evaluate the effectiveness of its compliance efforts.
As part of these efforts, Callsto, LLC has analyzed its traceback data over recent months and observed an overall reduction in traceback volume following the implementation of mitigation measures and stricter downstream controls.
For example, traceback volumes over recent months are as follows:
- February 2026: 8 tracebacks
- March 2026: 20 tracebacks
- April 2026 – Zero
- May 2026: 4 tracebacks
This data reflects a downward trend in traceback activity, particularly following enforcement actions, customer terminations, and downstream provider controls implemented by Callsto, LLC.
Additionally, Callsto, LLC has identified and taken action regarding downstream providers associated with higher traceback volumes.
Callsto, LLC continues to monitor downstream providers closely and applies enhanced scrutiny, traffic controls, and enforcement actions where necessary.
These measures demonstrate Callsto’s ongoing commitment to proactively reducing illegal robocall traffic and strengthening compliance with FCC regulations.
Cooperation Commitment
Callsto, LLC fully supports industry traceback efforts and remains committed to cooperating with the FCC, the Industry Traceback Group, and other stakeholders to identify and prevent illegal robocalls.
We are prepared to provide additional information or supporting documentation upon request.
Please direct any follow-up inquiries to:
Zeeshan Ahmed,
President,
zeeshan@callsto.net
Callsto, LLC,
1621 Central Ave # 9747, Cheyenne, WY 82001
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