Cancelled contract but still billing

Dear Telkom

Re: Acc ***1

I have received the worst treatment from you after been the loyal customer for 4 years, paying my install fees religously.

You have forward me to the Nudebt Debt collectors after cancelling the contract, on top of that you have blilled me the invoice i dont understand. I have sent you an e-mail on the 09/09/2024.

Why have you forward my account to debt collectors without responding to the query ?