MTN PADDOCKS MALL

I Visited MTN Paddocks mall last year december. Taking out a contract of one eof their black fridat specials. Ive been dealing with mtn for the past 3 years, and they have never deducted more than what they should. When i took out my second contract at paddocks mall. Im having problems, they keep on deducting more then they should. Or more then i signed for. When i phoned in this morning after seeing my debited amount, i called the MTN paddocks branch and the lady coulf not assist me properly. The obly thing i git out if her was, i have extra usage on my acount and that us why i pay more then i should. Thats bull**** , as i have been paying the same amount for a year already, why do i only hear today of exrra usage. Those things were never communicated to me.