Pathetic system

I felt extremely embarrassed at Makro on Sunday. Decided to use my Game Store card for the 1st. It declined twice. Yet I know my account is up to date and there is sufficient credit. The cashier even did a balance enquiry and confirmed there was sufficient credit. She called her supervisor. Whom explained it's showing and outstanding balance.. however that outstanding balance is for installment that is due 1 September. I tried explaining to them however there was nothing they can do. I had to pay cash... almost R900. Have never felt so embarrassed before