Incapable of handling anything out of the ordinary!!

I have had ***** committed twice on my cellphone contract. The first time it was resolved reasonably efficiently. The second time a credit note has not be passed for the items which were **********ly added to my contract and MTN is harassing me for a balance exceeding R51,000 when my normal cellphone contract amount is R311.50 per month. In spite of numerous calls and e-mails with various people since mid August, there has been no resolution to this matter and no response from MTN to any of my e-mails or visits to the MTN branch to lodge a complaint. I am constantly being harassed to pay the outstanding debt and my service is being suspended regularly which means that I can't receive sms's which I rely on for banking etc. There appears to be an appalling level of ***** and lack of management at MTN.