Elderly harrassed by SSDA

Absolutely useless!! My father is 90, lives at frail care, is deaf, almost blind and cannot walk. We cancelled his CellC account May 2022. Now we are being harrassed by SSDA for account arrears!? I have sent email upon email, phoned too many times to mention, only to speak to useless people on the phone who tell me to send the POA and POR over and over and over again!?!?!?!?!? And they need to speak to HIM or they cant help me. Good luck with that SSDA - HE IS DEAF!!