Deducting payment before the contract date

I would like to know who gave dial direct permission to deduct the installment before the contract date?? I have been I client by them for 2 years. Last year the same thing I phoned and said I DONT GET PAID EARLIER SO DONT DEDUCT THE MONEY EARLIER BUT NO ONE LISTENS TO THE FACT. Who is going pay the banking costs for bounced debt order as there was no agreement to deduct earlier or any communication. Explaination please.