Visitor
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4 Messages
Formal Complaint – Unexplained Data Usage, Unidentified Devices, and Poor Customer Support
I am writing to formally lodge a complaint regarding an unresolved and serious issue with my Comcast/Xfinity internet service, along with the inadequate customer support I’ve received in trying to address it.
On a single day in early June, I received a usage alert stating that I had already used 75% of my allotted monthly internet data—in just one day. This is highly abnormal, as my household setup has not changed at all: same number of people, same devices, and consistent usage patterns. I immediately contacted Comcast support to understand the cause.
Instead of a proper investigation, I was told not to worry, as I wouldn't be charged for data overages this month, but I would be starting next month. This completely misses the point. I wasn’t asking about fees—I was asking why such a massive spike occurred, what device was responsible, and how Comcast could not provide an explanation despite me using their own modem.
When I pushed for answers, I was told to “just sign up for unlimited data.” This is unacceptable. Why should I be expected to pay extra for a service I don’t require, especially when the root cause remains unexplained and may stem from Comcast’s end?
While troubleshooting, I discovered 10 unknown devices labeled “CTDI CMTX” (which appear to be Comcast-related) showing up as active on my network. I have no knowledge of what these devices are, how they appeared, or why they are consuming data. Comcast agents could not explain their presence or verify if they were responsible for the usage spike.
Since then, I have spent hours on phone calls and chat sessions with multiple agents, providing the same information repeatedly. I have screenshots proving that:
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Agents did not read prior case notes, or claimed they didn’t have access to them.
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I was asked irrelevant questions (e.g., “Is your internet working?” “Is this a billing issue?”), despite a case already being opened.
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I was forced to repeat my name, address, and the entire issue from scratch each time, despite referencing the case number.
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No effective escalation occurred, and I received zero follow-up from anyone with technical authority.
This experience has been incredibly frustrating, inefficient, and reflects poorly on Comcast’s customer service systems. A case should serve to prevent repetition and escalate unresolved issues—not force customers to chase down answers for days.
I respectfully demand the following:
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A full investigation into the unexplained data usage on my account.
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An explanation of what the “CTDI CMTX” devices are and how they appeared on my network.
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Confirmation that no unauthorized access or data usage has occurred.
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A summary of all case history and actions taken.
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A written resolution from Comcast acknowledging the issue and outlining how it will be addressed and prevented going forward.
If this matter is not resolved promptly and transparently, I will escalate the issue further by filing complaints with the Federal Communications Commission (FCC), Better Business Bureau (BBB), and Consumer Financial Protection Bureau (CFPB). I am also prepared to share this story publicly, as the hours of time wasted, the lack of accountability, and dismissive treatment are simply unacceptable.
Sincerely,
Binny [Edited: "Personal Information"]
Case #: [Edited: "Personal Information"]
EG
Expert
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111.5K Messages
25 days ago
Concern moved here to the Customer Service help section for greater exposure to Comcast corporate employees (The Digital Care Team) for assistance.
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XfinityRay
Official Employee
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3K Messages
25 days ago
Hi there, user_a8w7uh! Thank you for reaching out about the data usage you saw and the devices connected that you don't recognize. Seeing those devices can indicate that the POE filter to your home is broken or missing. We can get a technician set up to address that.
Please send us a direct message with your full name and complete service address to “Xfinity Support”. To do so, click on the direct messaging icon located at the top right of this forums page.
Here's the detailed steps to direct message us:
• Click "Sign In" if necessary
• Click the "Direct Message” icon (upper right corner of this page)
• Click the "New message" (pencil and paper) icon
• Type "Xfinity Support" in the to line and select "Xfinity Support" from the drop-down list
• Type your message in the text area near the bottom of the window
• Press Enter to send your message
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user_qwhvog
Visitor
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4 Messages
17 days ago
I'm having exactly the same experience, starting June 15. Was this matter was resolved? If so, how? If not, what is the current status? If this is ongoing, I'd like to know the claim numbers of the complaints the customer filed with the FCC, BBB, and CFPB. I'd like to add my negative experiences to those complaints and I'll pursue state-level consumer board filings, too.
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