MTN's way of doing business is questionable....

I have migrated to a cheaper package over a year ago but my subscription amount was never updated accordingly. If I do not pay the "full amount" by the due date each month, my line gets disconnected. I have reported the problem to the consultant who did the migration (Portia at the MTN store in Mimosa Mall in Bloemfontein). I was asked to send through my contract (as it would take MTN too long to retrieve it from their system), which I did twice. In January this year Portia promised to resolve the problem. Two weeks ago I have received an sms which says that the problem has been resolved and the matter is considered closed. Nothing has been resolved!! I still have to pay the original amount to keep my line active. This is nothing less than *****.