Returned defective device from insurance claim shows accepted at USPS and received at authorized facility for AT&T charged non-return fee

Submitted an Asurion claim for device replacement approx. September 22, 2020..Returned device in box and return label provided by AT&T.

I have receipt for USPS acceptance 09/24/20 and verified tracking number show receipt of device at authorized AT&T facility 09/28/20..and yet I am told per the Trade In support team that the $650 defective replacement device has not been received and my service will be suspended. I was told that I will eventually be reimbursed over time. I spoke with a billing representative today who advised that there's nothing that can be done and it's unfortunate and my service will be suspended if I DO NOT pay the additional $650 with my regular bill by Dec, 24 2020.

With proof of receipt why can't the charge be removed? I have proof that the charge was assessed to my account more than 6 weeks after the verified receipt of the defective device at AT&T's authorized facility.. Please help!!!!!