Self Funded Credit Card but owe FNB money?

I requested to close my business credit card account a few weeks back and I am unable to as FNB says I owe them money. I wanted to close both of my accounts - the control account that always has R500 in there and the actual credit card. The control account was also funded by me as no credit was extended to me by FNB.<br> <br> So this has now been going to FNB and back to me for a few times now and all the times I still dont get it. This time they sent me statements saying that I was R490 in credit. So I tried to access the credit card statements but that account has been deleted off my online banking. They were both in credit the day I closed my accounts.<br> <br> So now please answer my question, how can I owe FNB money if the card was self funded and I did not exceed the credit balance at all? This matter has been dragging on forever and I would like some closure on this matter.