Poor service

Good day

on the 6th September 2021 i called your office to update the banking details of the person loan i have with use , i told the agent that he needs to update the details to the revolving loan details as my salary goes into the fnb bank account, the funds in my saving account is a saving account , i received a sms to say the details has been amended ,on Saturday the 25 September i received a notification that the installment went off from mt savings account ,

firstly the debit order date is incorrect Secondly what if there was no funds in that account the debit order would have been unpaid and reflected negatively on my profile

i am phoning every second day to update the bank details and no luck