They refuse to correct my address

I took a contract with MTN last year over the phone, gave the agent all my correct information but she has my address totally wrong. Has me living in Gauteng and I live in KZN, have actually never stepped foot in Gauteng. I have asked, begged and even threatened them to correct this but it's just not been done. My worry is that if they keep using this address, it will become part of my profile. I really don't know what to do anymore.