Ridiculous and Humiliating

I have a RCS Pick n Pay store Credit Card Facility. This is the worse service/facility EVER. I pay R5000 into the card and when I want to swipe for R4000 groceries, it declines because according to the it "flagged an alert because it was a large purchase" I have never me a ******** who would steel a card, make a payment on it and then make a purchase on that card for a lesser amount. Needless to say I feel humiliated each time a purchase is declined and I have to ask the store to phone RCS to authorize a payment on my card because the store does not have cellphone reception once you enter the door.