Why is the debit order date changed?!

Hi, I received an email yesterday notifying me that my debit order will be moved from the 25th May to 24th May. This is a problem, as there will not be sufficient funds in the account. I only get paid on the 25th of every month!!! I phoned you and was advise by the lady that the sms was not factual and to just ignore. Today I received the same sms. Who will be paying the charges for the return of the debit order?