*****ulent contract and no response from MTN

I have been trying to contact MTN after a *****ulent contract was taken in my name , about R10 000 debited from my bank, I switched banks and I only found out from debt collectors and transunion , been sending countless emails to MTN , no response , if I go to the store I’m only told to call 083 135 - I never get through to anyone because I don’t use MTN. Been told it’s with the legal department , it’s been over a year now and this affected my credit score negatively.