Telkom is messing up my future - my home loan - lying about my bad credit

Telkom is ruining my credit score which is not my fault. They are *******.

I took up a Telkom contract last year for uncapped LTE. Initially the service was good. However, started to give issues. My wife and I tried to solve it via the call centre, emails, the app, and going to various Telkom stores in Gauteng. Nothing worked.

While this was all happening. Telkom decided to still take money out my account every month. Like clock work. Eventually I got fed up, and blocked them on my app. Various references said that my cancellation requests were logged, successful, complete.. yet when I am trying to apply for a home loan, I get told that I have a bad credit score and I owe Telkom money for something they did not deliver on. This is not fair. All my other accounts are up to date. Why Telkom? Why are you doing this?

If anyone has advise on how to solve this. Please help me. Please. I am trying to start a family and need a home.