Bad MTN Service

Greetings, i have had an absolute terrible experience with my MTN Contract, its been months now trying to resolve this issue and nothing yet...what happened is i asked for my balance so i can pay my account off when i got it they took 3 months to allocate the funds and then they told me that its accumulating every month where as i have paid on time...this is frustrating me and blacking me from doing a lot of things , please help me