billing for equipment i do not have

I moved from San Francisco to Philadelphia in May of 2024. The last task I did was returning my internet modem to the Xfinity store. When I set up my internet at my new apartment, Xfinity sent my new modem to my old address in San Francisco, even though I had given them my new address. I explained to them there is no way I can go back across country to pick up the modem that they mistakenly sent there. There is a chat log somewhere where an agent apologized to me for it, and sent me a new modem to use because I had to work. I just found out that they are STILL BILLING ME $15 a month for the modem they sent to the WRONG address. I have no one there who could help me, I was not going to fly back to San Francisco to fix their error. I realize I should have looked at my bill, but I didn't think they'd continue to charge me for THEIR mistake. I just moved again and noticed it looking at my current bill. So I am out $200 for their mistake, and my bill says they will continue to charge me until I can return the equipment that they mistakenly sent. I have been trying to talk to a human being but it is IMPOSSIBLE. Where are all the humans working at Xfinity??? Even when I click on the BILLING option in the chat, it says it cannot help me. So no one can talk to them about their bill? Looks like I am going to find better internet options for me. I am not going to fly back to San Francisco to fix their mistake. That is insanely ridiculous.