Billed after cancellation

I cancelled my account over the phone on 11/22/2021 and received an email confirmation of the service being terminated on 11/23/2021. Today I just received a bill for next month's payment and I checked my plan on the website to see if it actually got cancelled and it looks like it hasn't been cancelled yet. Over the phone, the rep even confirmed that I would be RECIEVING credit for the prorated amount in November. Why hasn't my service been cancelled yet even after all of this? The chat bot always tells me that a rep isn't available and to call in. I've tried contacting support multiple times on the phone and the call attendant bot crashes so the call ends, and I literally have to try calling upwards of 12+ times.