Upset as hell

I've been an MTN cuztomer for well over 20 years and I've paied my account withoit issues. I don't likw debit orders sonI paid my accont via EFT all the time. I get paid on the 25th of each month and that's when I normally pay them. Suddenly they switch of my line before the 25th and say that I'm paying late and that cash customers has 21 days from statement to pay how does that make sense???? I get paid on the 25th and that's when I can pay. Everyone get salaries month to month how are people supposed to pay before then. This is crazy and must go to the ombuds man.