MTN Contract Braking!!!

From March this year my invoice on a statement from MTN was completely wrong. I have sent them numerous emails and called them many times. Still to this day my I am paying 30% more on my MTN contract each month. This is totally a breach of contract regulations and MTN, you are *****ing my money!!! I have been a customer for the past 10 years!!! You will never get any business from me again!!