Wrong billing information (credit card) on my xfinity account

April 5, 2025, I noticed that my Xfinity home internet bill is charged from my correct card but my Xfinity mobile bill is charged from some unknown card. I looked at the billing information and I have no clue whose card Xfinity has put on my account. I reached out to customer service via chat and they told me that the xfinity mobile billing information (credit card) on my account was updated July 12, 2024. I asked them to fetch information about where it was updated (at some store near me or somewhere else) or the IP address of the device used to update that information because it was never done by me. They did not share that information. That unknown card has been getting charged for my bill from July, 2024. I do not think that just changing the billing information from my end now is the solution. I need to know why this huge mistake was made by Xfinity. Also, it is crucial to inform the card holder that their card was incorrectly charged by Xfinity for this long. I should re-emphasize that the credit card information was never updated by me. Please help me with this matter. I need to know who updates the credit card information, where it was update (place and device information, possibly IP address or something like that). 

Apparently, there is no email to contact xfinity, so I have no option but to put it here. There is no direct message on the website either, just AI agent and live agent chat. In my previous experience, xfinity store employees completely disregard that information provided by the live agents on the chat. This means that anything said by the live agent on chat is useless and cannot be trusted. Please help me escalate this issue. In my view, this is a big concern.