Incorrect $100+ Equipment Charge After Equipment Return

I need this issue escalated because I am extremely frustrated.

On 7/24, the exact day I returned my Xfinity equipment, the store told me their system was showing another piece of equipment that needed to be returned. I told them I did not have any additional equipment. I contacted customer service that same day, explained the situation, and was told not to worry about it.

On 8/3, Xfinity contacted me again about the equipment. I explained that I had already addressed this with customer service and was told it was taken care of. I asked you to stop contacting me about it.

Now, on 9/12, I have received something in the mail saying that I owe Xfinity $100+ for equipment I never returned.

I tried to resolve this again through the support messaging on your website, but I was told to call. When I called, I was told that my phone number is not connected to an account and therefore I cannot be assisted. Yet I am still receiving mail from Xfinity claiming that I owe money.

This is unacceptable. I returned all of my equipment on 7/24 and do not have anything else to return.

I need Xfinity to investigate this, remove the charge, and confirm in writing that I have no outstanding equipment balance. Please also ensure this is not sent to collections or negatively reported while this is being resolved.

I left Xfinity because the rates no longer fit my budget, but the experience of trying to cancel my service and now having to deal with this issue has been incredibly frustrating.

I am not paying $100+ for equipment I do not have. Please resolve this and let me know what, if anything, you need from me.