MTN Customer care center - Shocking bad unhelpful service

After receiving a Invoice on my monthly statement for R9648 (vat included) that does not belong to me, and MTN debited my bank account with this amount - I have tried numerous times to clarify/rectify this. I made contact with the local MTN dealer, who logged a complain, I phoned the "customer care" center numerous times at 135,0 - got a Reference number that gets me a SMS message from MTN "..query has been resolved resolved" - Phoned again and said it is not resolved - then was explained it was send to Tech support instead of Billing, but now it will be investigated.. Then again "Dear customer...your query has been resolved....... NO it IS NOT RESOLVED! How is it be possible to stay loyal to such a company? What can be done next - Phone 135,0 ? :-(