Miss selling and inability to cancel contract.

I have an MTN contract that should have been payed up 2 months ago. On cancellation I found out that I had 2 other MTN numbers registered to me that I was not aware of. On taking my contract I specifically asked to not change my current number and only required a cell phone contract with NO data or minutes. I found out that 1 number was for my phone. 1 for data and minutes. I had never used any data during the 2 years of my contract. I was billed incorrectly and unfairly and was sold a product without my knowledge. I have never once used that data or sim card. I have since even been charged for an extra 2 months after my contract was supposed to be cancelled. I have been sent from pillar to post just to try and cancel this contract.