Nedbank does not want to close their credit card

I have settled my nedbank credit card account and I called the call center in December to close, althou I must say as well the consultant was just passing the buck not efficient or effective at all didn't even ask me the questions I was hoping to be asked. And then just said my card was closed, and I asked how can I be sure she said I'll have to call tomorrow to find out that is not her job to confirm. What she did was close the account, now I get a statement which says I am owing some money and my account is not closed. *** is that Nedbank, I need my account to be closed now