Cannot close an account

I have been trying for 6 weeks to close my credit card account. This account is fully paid up. I was told that it would be closed at the end of February, which failed to happen. I have spent countless hours on the phone, had two reference numbers, emailed countless times with no joy. they are charging me fees amounting to over 350 Rands so far. Surely it is within their competency level to carry out a simple request.