Transferred Service, got billed for early termination of contract.

Cancelled service at old residence on or about October, 24th, 2020. After a delay in closing on the new residence, I restarted (should have transfered) service there on or about December 1st, 2020. I received a bill for service at my old residence with a charge that represented, I was told, the charges for early termination. I was given a number to call by a CSR in a brick and mortar Xfinty store to resolve this billing issue. Spoke with CSR by phone appointment, explained the situation and asked the CSR to waive the penalty charge for my cable service as the service had been transferred from my old reisdence to my new residence. He told me he would take care of it. The charge is still appearing on my closed account at my previous residence as an amount due. It does not appear to have been waived as I was told it would be. Solutions?