AVAF continuously takes R9500 instead of R6991 from my account

This is the second month in ow where Absa vehicle finance goes into my account and deduct R9,542 instead of R6,991 monthly instalment. I cannot be expected to go through the process of fighting for a refund every month and be grossly inconvenienced by having other debit orders bounce because of your mistakes. Please can you resolve this as I have more debit orders to pay tomorrow.