Payment Allocations not being attended to timeously

Pick n Pay is always very fast to send my mother messages BEFORE the due date to pay her store account, however when she has paid in store a week before the due date they take their time to allocate the payment, so she can use the card to purchase food.

She paid on the 26th of October at 11AM at PnP in Van Riebeeck Park, Kempton Park. However, now on the 27th at 8PM when she logs into PnP online her payment is still not registered for her to be able to buy.

The call center only tells her to wait. What would happen if she told them to wait for their payment?

This is not very good customer service at all!