Impossible to unblock credit card of Discovery Bank

I have had my credit card locked/paused by the fica department. They requested all sorts of paper work and do not accept my proof of residential address which is not the same as our erf no or postal address. I have spent hours on the telephone with them and have sent many requested papers but now they want a whole lot more. Nothing seems to satisfy them. It seems to be an impossible situation and they obviously no longer want or need my business. I have had a credit card for a number of years, and now they seem to be totally unreasonable. My best recourse now is to cancel the card. Useless fica dept!