Wrongly being on arrears of R550 from MTN

I've been having issues with this service provider, MTN; my credit check reveals that I owe them R550. I've visited to their branches, and they've told me that I don't have any outstanding balance; instead, they owe me R0.56 cents, and I no longer have a contract with them. I've been applying for crucial items like housing, clothing accounts, cellphones, and other things, but I've always been rejected, causing my credit score to plummet instantly. They always say that my loan is paid off, but I know it isn't. This is negatively impacting my credit score. Like today, Tuesday, 04/11/2024, I received a response from an agency that I app**** for social housing to, and they suggested that I should contact Credit Bureau or TPN to confirm that the amount has been cleared of which it is since this year July 2024. I'm really devastated with them please help me.