Take forever for a letter

I paid off my credit card and asked to close my account, requested a paid up and close of account letter, the consultant gave me a wrong amount to pay off, which I did but later to find out that I had over paid. A week and 2 days I still had not gotten my letter nor my refund. When I call every other day to enquire I am told still in progress, on Fri, 24 Feb I phoned again to be told that the matter is still is progress, on the 01 Mar I followed up again and was told that the letter is automatically be generated and sent after 5 working days. Today, 03/03 is the 5th working day, I called again to be told that I should get the letter by Wed, 08/03. I am not a happy customer because African Bank was able to provide me with a letter same day I paid them off and closed off my account. I thought Nedbank is a more established institution than African Bank, but nooooo, I was wrong. Never giving Nedbank my business ever in the future.