Debit date moved with no authorization

Nedbank Please advise me who gives you the authority to move my debit date to an earlier date? The fact that the normal debit date falls over a weekend does not give you the right to move the debit date earlier. You send me several, in excess of 6, text messages just "informing me" And when I try to call, I get placed on hold. My salary is not paid earlier. I am warning you, do not attempt this debit on an earlier date, I will not be liable for any unpaid debit fees.