TRACKER HANDED ME OVER TO LEGAL EVEN THOUGH PAID

I had a car which I had tracker system installed in. I sold the car but tracker still billed me for my remainder of my contract period. In March 2014 I agreed to settle the account. I paid the account in full. I requested a confirmation letter from tracker that my account is paid in full and that it is closed. They then said they can't close the account unless I pay R 400 cancellation fee. I paid the R 400 and received a letter stating my account is closed and settled in full. To date I am still listed on ITC by tracker which states I am handed over but the letter clearly states my account is cancelled and that I own them no money. The letter also states that the credit bureau will be updated accordingly which has not been done - I have now negatively been affected on my credibility and can't obtain any finance due to this. I have strings of emails confirming communication to all the relevant parties at Tracker but to date they have not been able to solve the matter and they also lack in communication - it takes them days to get back to me and they also keep on shifting the blame. No one wants to take responsibility for their mistake and instead i am left with a poor credit report.