Bad account management!

I had an contract with MTN 4 years ago I had to upgrade when I got to the store they where busy upgrading their system (I live 3hours aways from my nearest mtn) I returnd a week later and still the could not help me..I got a prepaid simcard for time being as my sim also gave me problems till today 4 years later I have not yet upgrade and I have a bill against my name of MTN everytime I call in I am on the line for 2hours plus and no one can assit me because it appears to be all on the old system I have been put through to that Attorneys that thay use and they cant even help me they see on the system that I have an arrear against me but no one seems to know how to get access to it or resolve this matter I am very upset and disappointed as This is stading in the way of my home loan and my vehicle financing when will this be resolved????I drove 280km twice to a branch and they dont even know how to assit I emaild the head office with help of an mtn branch and cc me in the email and still no reply 2 months have passed and no call back from Attorneys either mtn quick to take your money but no service!