Paid up account yet im not cleared

I had a contract with mtn, and I was handed over. I made arrangements with Norton Lambrianos and made a full payment. they refuse to give me a paid up letter saying MTN took back my account and is now handled by them. fast forwarding to today, I made an application and was told my account is still outstanding and still handed over and gave me the legal(Norton Lambrianos ) contact no. I called them and they told me to call mtn as they are now handling my account, called mtn back again and they still not assisting and referring me back to the lawyers. this is so frustrating and im moved from pillar to post, clearly this will never be resolved. what will it take???