Poor service - Re contract cancellation

I cancelled my Vodacom account at the end of June (effective 2 July 2021 - contract was active for the full 24 months). After multiple attempt to sort out my account the last month's payment was eventually sorted.... Thereafter I received further accounts for promotional items that was on my contract - even though I cancelled everything. This took more time to resolve, my understanding was that it was corrected.

Now, (3 MONTHS LATER) I have apparent outstanding balances with Vodacom which is showing at the Credit Bureau and negatively affecting my credit score. It took me 1.5 hours and 3 departments, explaining my problem multiple times, transferred from prepaid to contract to accounts with no luck. I can't call collection/cancellations directly since my number is prepaid. So I need to call via various channels to talk to someone who MIGHT be able to help me. I'm fed up with the service I receive from Vodacom since cancelling my contract.