account paid but mtn claims overdue

Since the beginning of the month of august, mtn started to send me smses stating that my account is overdue. They even suspended my lines just after I made a payment for June and Jule. They had a nerve to tell me they suspending line because u didn't make a payment. I had it with mtn that does this to me when I make payments. Is it my fault that their systems are not updating client payment details? I refuse to believe that I owe mtn I can go get bank statements that I know I paid. I am tired of mtn making as if I don't know how to pay my debt. They must get their facts in order before harassing me with silly smses that my account is overdue this is really annoying and unfair when u receive these messages yet you know that you paid!<br>