FNB Homeloan Department Cape Town

For 19 years I have had a split payment for the payment of my home loan, I decided to change the salary stop order to a debit order and was requested to complete a debit order authorisation form for the deduction of my instalment. My debit order athorisation was completed for the amount I have been paying for 19 years and the balance is as per usual, paid via cash deposit. For 2 months FNB deducted the full amount due without me consenting to it. What is the reason for completing a debit order authorisation when FNB disregards it and deducts whatever amount they want to. It's *******!!!!! to deduct amounts without the account holder authorising it!!! what is the purpose of their "Debit Order Authorisation" form if its disregarded???? My other debit orders on my account now goes into arrears because of insufficient funds in the account...snowballing into bad reflection on my credit, gathering penalties for non and late payment and what does FNB say after numerous calls requesting an override to accommodate a new deduction date...... we're sorry we are unable to. So not only do they use their own right to deduct whatever amount they want to from your account, they also cannot change the deduction date in order to ensure sufficient funds are in the account to cover all debit orders!!!!! 19 years of being with FNB homeloans ...19 years and for what??? Day 4 of escalation and zero can be done