MTN pathetic service

I have been trying to cancel an MTN contract since lockdown, initially through the call centre which I could never get through to and then by visiting the V&A Waterfront branch early December, the staff member at the store was very helpful and provided me with a reference for the contract to be cancelled and the assurance it was done, I asked when the last debit order would go off and was told that there would be no further debit orders. End December surprise surprise the debit order goes off, once again I go into the MTN shop at the mall in Swellendam, the assistant looks up the reference number and the cell number and informs me the contact has been cancelled, only to receive today a new statement and invoice for December and January, therefore obviously no cancellation has been processed and I'll have to cancel the debit order again