DEBIT ORDER DISASTER!!!

Bought a vehicle and my FNB account number to be debited monthly was captured incorrectly. 1st Months payment in arrears - forced Absa to do a once-off debit order from my FNB account, came off perfectly fine. Instructed ABSA to fix the account number. 2nd Months payment in arrears - spent a week at an Absa Branch to sort it out. Still in arrears and no debi-mandate to approve on my FNB side. No 2nd once-off debit order as promised, there goes my credit record and Absa will probably add interest. ABSA, HOW DO YOU EXPECT THE DEBIT ORDER TO COME OFF MY FNB ACCOUNT EACH MONTH IF I DO NOT GET A MESSAGE TO APPROVE THE DEBIT ORDER MANDATE?