Poor service, Unable to cancel contract.

Good day, I have been trying to cancel my Vodacom cellular contract since June 2020. Every time I call the call center, I get told that the contract will be canceled at the end of the month, but it never does. They also say a consultant will call back to confirm cancellation and that never happens. I call back and they say the consultant that was supposed to process the cancellation has not completed the procedure. They have even promised to refund me, In my opinion this is all lies. How can a large service provider like this not have a proper cancellation procedure and not followup accordingly? When are you going to cancel my contract Vodacom?