worst service and falsely handed over

I have been battling for almost 8 months now to clear my name at MTN which was a human error made by the instore officials incompetence to cancel my contract on the system after paying the early retention fees in Feb 2022. I was legally handed over for a amount less than the settlement and put on the credit bureau. this is the worst service and company I have ever dealt with. the manager of a MTN branch could not even assist and advised I must speak directly to Legal department which is a battle to get through on the 083135 number....how must this be resolved, by following a legal process which will cost me unnesessary fees which was dealt by the MTNs *********** instore official.