Cancellation of expired broadband contract

I sent the required cancellation form on 20 December and again on 11 January to the cancellations department email address. You cannot do this at the counter. I have had no acknowledgement of receipt, no case number, nobody has phoned me. Subsequently I have contacted the call centre number on the cancellations form. There is no option for cancellations. My call was answered. Nobody could help as nothing was registered on the system. I asked to speak to cancellations but was told they do not have a number and cannot be spoken to. Seems I am doomed to pay for a service that is not required or used. Telkom have designed a system that locks customers in forever. Please somebody contact me.