FNB are you that desperate for money or simply totally ***********?

This is now the second month that FNB has debited the minimum amount for my wifes card to her current account, despite having instructions to debit the full amount, which has been confirmed both times by the FNB call centre and last month by the card collections division as well, and is stated on her card statement. As a result when she noticed what they had done she immediately paid in the balance, the next day. Last month they made some asinine excuse that although they saw the instruction it would take a full month to be activated, which I find incomprehensible. So of course the interest was charged, which they refused to credit back despite it being as a result of an error on their part. The only reason I can surmise that they are debiting the minimum amount, which obviously she can only see the following day, is so they can charge interest, despite her having paid in the balance, as last month, the next day. Or of course, that FNB is grossly ***********. It will be fascinating to see what the excuse will be this time.