Shocking service on Standard bank card.

I have paid up my Standard Credit card at least 6 months ago. I keep getting statements with amounts due. I went into the Walmer Park Port Elizabeth branch on Tuesday 7 January and requested the card be cancelled. I was then told by the agent that there is an amount due for charges. She said she would phone me back today which she did. Over the weekend I received an SMS from SB stating that I my credit card balance was 254.94 which I paid via immediate payment from my FNB cheque account. Today I got the call from the lady from Walmer stating that I need to pay a settlement amount on the card. I havent used this card since paying it up months ago. I told her that I see this card as now paid up due to the amount paid and she argued saying that its not paid up.