Nedbank can not cancell my American Express credit card

I have canceled my Platinum and American Express credit card sometimes in September 20219. For some reason only the platinum credit card was canceled. On the 27/12/2019 I received an email with a statement which had a balance which came as a shock to me because as far as I know that American Express credit card has been cancelled. I called the customer service the following day to understand what is happening I was told they will investigate and revert back to me. I waited until I decided to call them again in January where I was told the other credit is cancelled and the American Express credit is still active with a balance I requested a recording of my call since they always say it recorded to date am still waiting. I called again last week to inquire about my complaint I was told to call retention where I was hold endlessly without a response. I went to the branch where I was told to call customer service again. The only thing am asking from Nedbank is to cancell the credit card.