Charges on canceled card.

I paid off my credit card and I cancelled my card online in May. I even paid extra.

Next thing I get a sms saying I need to pay certain amount. So I sent them an email asking them to close that account because I canceled the card and I don't understand why they are charging me.

A Rita Govender responded saying she will not be able to close my account until I settle the amount.

I then asked her why I'm being charged for a card that's already paid up. She responded by saying they can reverse other charges but they cannot reverse the interest. I asked her what the interest was for because I fully paid my account and canceled my card. She never responded.

They debited my account and I reversed it and sent another email asking them for feedback, to this day I have not received feedback. I'm very unhappy about this and I need feedback urgently.