Where is my credit?

I have had my Foschini account for almost 15 years. Last year Sept/Oct I paid my account in full. I did not buy anything again, until January. Then I found out that I don't have any credit, due to an amount due of R89. I phoned the call centre, and the lady told me as soon as I pay that amount, my credit will be restored. Now I had credit of over R11 000. Next day I went to pay the amount due, which all of a sudden was R109. I did not pay attention to the credit, and since I did not receive any statements due to the Post Office strike, I only recently received my statements, and saw that my credit is now only R1500. What the heck? I am really angry over the fact that it was said my credit will be restored, and over R89 (Foschini club or whatever), my credit is \missing"R10000. Please explain???"""