Revolving Loans

FNB Revolving Loans - every month I sit with the problem that payment is deducted from my account via debit order and then my loan account gets put on hold and they say payment overdue and can't access the funds available. They say it is because of public holidays or weekends but funds reflecting on my loan account and cleared. My debit order date is the date my salary gets paid into my account but they try 3 days before the time already for payments. Why do you select a payment date and debit order date if they just do what they want. I've tried to chat with a consultant today at the revolving loans department on secure chat but since 10 am no advisor available to assist. It is now already 13h20, I'm disappointed in the service I'm receiving as an FNB client for a long time and this started all of the sudden from beginning of this year.