Help me close Credit Card from Nedbank

Being trying to close my Amex Credit Card with Nedbank via the banking app, All I get is the relevant documents for cancelation have been sent to the relevant department check after 3 days. After that 3days no changes just charges and I started this process in June. Tried calling them they called a day after then told me not to close it but decrease the amount. I told them no just close it. I was it's closed check after 7days. Welp the Card is still generating charges till to day.