BLACK LISTED DUE TO POOR ADMIN AT FOSCHINI

After been a customer of Foschini for more than 30 years and never ever missing a single monthly payment = I would be classified as one of their BEST CUSTOMERS, Foschini have taken upon themselves to ignore every single email, post, fax & RECORDED telephone conversation telling them of their ERROR. I have subsequently been BLACKLISTED for monies which I do not owe and now cannot get funds for urgent Student Loan for my son or any other funding I require due to THEIR NEGLIGENCE. <br> Problem started when Foschini decided to issue me with a NEW CARD (I didn't ask for it), I continued paying my regular monthly payments without realising my monies were been allocated to my OLD CARD NUMBER and not to the ACTUAL ACCOUNT NUMBER.. Took almost 2 years for me to explain myself over and over and over again as to their problem, when they finally got it, they credited my account which I had by then overpaid by more than R800. I then went and made one more purchase and the problem started all over again and NO-ONE in Foschini Admin seems the slightly bit interested in amending their mistake even though it has been told to them 100 times over last 6 years. How do I get off the BLACKLIST?