Disregarding client mandate

I have opened nedbank account on the 3rd October 2024 and switched my salary, I instructed the bank to debit from my nedbank account as from 15th October 2024, to this day they have not done that, instead they busy trying to debit from standard bank account which does not have sufficient fund. Now RT not provided for, from standard bank who will be paying them since I accepted nedbank debicheck mandate for my vehicle finance loan MFC