Poor service and arrogance from Billing department

In August, I queried an amount that MTN claimed I used on my account. Safe to say, the amount changed from my data to voice line the following month and no one has bothered to call me to explain what the usage was for despite having proven to them I have never used that amount on dat for the last 36+ months that I had been a client of MTN for. I was then sent some validation statement which I requested that they explain but, arrogantly, I was told that the case is closed I must pay.<br> <br> In the same month, I gave notice of cancellation of my data contract which was expiring in September and I got confirmation email that it would be cancelled on 23 September. Indeed the primary line was cancelled but the secondary line was not. This generated an amount of 3000 by 10 November and I have been fighting MTN to explain how that happened but have been given countless ref. # and no one has bothered to have the query resolved as I am told it's a billing issue and they don't take calls but are the ones calling the shots. My contract is expiring in February and want to move my contract but I want my number. Can I just have someone explaining the story to me. I am tired.