Close your income generating account on interest!

I have been trying to close my credit card account for over 6 months now after paying it off. Everytime I call, I am told there is a balance owing. An interest fee that they are charging on my account. I am closing because of that very reason. Other banks like FNB don't charge when you have not used any monies. Tried waliking into the Woodmead branch, was assured it would be closed the following day becasue they could not close due to movements due.Tried to call today again and told same old amounts due on interest. I AM FED UP! Please close this account of yours.