Bad arrogant service

Goodday, MTN made a early deduction of my monthly premium without any permission. I question this and request the money paid back to my account as I see it as theft, my money were taken without my permission. According my contract they have to deduct the last day of each month. After I question MTN ,they suspend their service to my devices, I cannot make calls. I have 4 contracts with MTN and this is how customers are treated, I think it's blatant arrogance from them.