2 years of canceling a contract that is not happening

Cancelling of contract just not happening. I have been trying to cancel a contract for an unused number for the past 2 years. I have been to the canal walk MTN branch more than twice they tell me I have to call their call center. I have called numerous of time with no proper help. I have emailed and have had responses saying the contract has been cancelled, But I am still being billed and the number is still reflected on my account. THIS is UNACCEPTABLE and extremely poor service. What else can a person do!!!!!!! Never mind even trying to get credited for the amount... A reference number apparently also mean NOTHING