Telkom Mobile open call now for 5 months

I have a Telkom LTE contract for my home internet use and have been having intermittent problems since January - up to today they have not been able to resolve the issue. Just been on the phone with them and requested either a refund, resolution or cancellation of my contract. The adviser advised that they cannot approve a refund, no time frame for resolution and if I try to cancelstop paying they will report it as non payment which will affect my credit rating. So basically I'm paying everyone for intermittent service I cannot cancel and Telkom is unable to resolve. Worst service ever!!!