RETURN MY MONEY ASAP!!!

FNB is supposed to debit my account for repayment of my credit card on the 25 of every month, which did not happen now this January, on the 26 I made my own transfer seeing the debit did not go off and I did not understand why. There was no sufficient funds anymore and as a result the debit returned with a R100 cost. I want FNB to return my lousy R100 back into my account, I did call their call centre and was taken from pillar to post with no assistance, was told stories of how many days it takes to clear and blah blahs which does not concern me because if you will tell me you will deduct money in my account on the 25th you supposed to only deduct then and not a day longer or else they should have said the debit is only on the day they claim it clears. I have another debit going off on the 1st of February and FNB should return my 100 before then because should there be a returned debit again, it will be in their hands to cater for the charges!!!!