Formal Complaint Regarding Unauthorized Debits After Contract Termination

I am writing to formally lodge a complaint regarding continued debits from my bank account for a data-only SIM contract that has already expired. My contract with Telkom ended last year; however, I have noticed that deductions are still being made from my account on a recurring basis. This is both unexpected and unacceptable, as I have not renewed or authorized any continuation of the service. I kindly request the following: Immediate cancellation of any active billing linked to my expired contract. A full investigation into why these debits have continued after the contract termination. A refund of all amounts that have been deducted from my account since the contract end date.