Moved debit order date without permission

Capitec moved my debit order to an earlier date, that is before my pay date without permission. Went to branch with proof of payment and was told they cannot change as some of the other workers get paid on 22. Now I receive sms' s stating I'm not paying. So I called them again to get them to move it to my payment date, but was told they cannot help. Even as I'm telling them I am getting penalised at my own bank for every time the debit is unsuccessful. It is costing me money to sort out their pathetic admin system as I have to drive to the next town every time or to call them from my cell.