THEY DEBITED MY ACCOUNT BEFORE THE PAY DATE

They are claiming that when I signed my contract which says last working day of the month not last day of the month.I feel that I was very misled because if I was not paid yet they went ahead and debited my account its unfair.I have cancelled my debit order and really feel that I was treated unfairly.I now have to pay R100 charges and also pay bank charges for the unpaid fee.