Incorrect charges

I cancelled ALL of my Xfinity services in-person at a store in Chicago, IL and returned all of my equipment on July 1, 2026. I double checked to ensure ALL of my services were ended (I believe they incorrectly ended them and mobile services were still active without my consent or knowledge). I then received a bill for $81.09 on 8/1 for an automatic payment to be taken out 8/21, after ALL services had been cancelled for a month. I contacted the merchant via phone call on 8/7 about the wrong bill and they told me that I would not be charged and that they took care of it on their end. I was charged anyways. I then reached out on 8/21 where I was promised a refund. After never receiving it, I reached back out on 8/28. They said I should receive a full refund within 1-2 days. I have yet received anything, and called back today 9/1 and the agent said she had no evidence of the charge. Now, I have received another bill. This is ridiculous. I am being charged for Xfinity mobile services that I never wanted in the first place, and it does not even show that I have an account or let me log in anywhere.