Billing

I changed both my internet and cell phone from Xfinity to att in June. You kept billing me after the switch. I called Xfinity and they told me the reason why was I hadn’t turned in my router. I returned it in August. You even sent me a refund. You were not supposed to bill me anymore. But just received a email saying you had billed and you took money out of my account.

When I call trying to fix this it asks for a phone number associated with my account. I type it in and it tells me there is no account associated with that number. The number is [EDITED: Personal information] You need to quit billing me and stop taking money out of my account and send me a refund for the money you have taken