Cancelled contract - still being billed

Cancelled my contract via phone end August/early Sept 2023, last payment made 02/10. On Nov 1 Vodacom submitted an additional debit order which I reversed. Vodacom is now negatively affecting my credit record stating 3 payments have been missed. This contract was cancelled!!! Vodacom, go back and listen to the recorded conversation held last year and fix this mess.