Proper payslip required

I've been a happy capitec customer for years and when I heard they now provided credit cards I wanted to move my credit card to them ASAP. I work for my parents and therefore don't receive formal payslips, so I had to make my own one (as I have done in the past for cellphone contracts), but it was not good enough. I asked the person on the other side of the desk to give me a list of what I need to put onto the payslip, but she refused. I thought that the fact that I have been a customer for a few years would mean they can just look at my past 3 years bank statements and see what I qualify for.