Impossible to cancel contracts

My MTN contract expired on the 31st of August 2018. I went to Shelly Beach Store, KwaZulu-Natal and asked if they can cancel the contract. They informed me I have to phone the customer care line, as cancellations aren't done in-store. I Phoned customer care, but the call center were not available. An automated message explained that because the call centers aren't available I must email ********** which I then did. On the 4th of September 2018 I received a email asking if I want to keep the SIM as a pay-as-you-go or terminate it completely. I re**** I want it terminated. It is now 3 months later, I have received no feedback and the contract fees are still going off my account. This is frustrating, because I have a new contract with another service provider and this takes my budget into overdraft.