Change debit dates without accountholder consent

Who gave Nedbank MCF permission to change my debit order payment date from 15th to 12th???. On 12 Sept they will get insufficient funds! Obviously there's a reason why they must debit on 15th! That's my PAYDAY! "....process vehicle finance on 12/09/2025 to match your salary date. To keep your date, please OPTOUT...."This is ridiculous. Obviously you must debit me on my salary date as per my contract. So I called the no.provided and instructed the consultant to OPTOUT on my behalf. Imagine if I missed this SMS!! What a predicament it would have caused for me not having their funds available! YOU CAN NEVER CHANGE DEBIT DATES WITHOUT THE CONSENT OF THE ACCOUNT HOLDER!