Trying to cancel contract

I have been trying to get through to the cancellations department since Monday, but every time I get put through, I get cut off. I want to port my number to another network, but when that network put in the request, it was rejected because MTN submitted my line through as prepaid, when I signed a contract! When I mentioned this to the call centre agent yesterday, after many calls there already, she basically told me that I was lying, as well as the other service provider. An urgent request was put through as well by one of the call centre agents on Monday already, for the cancellations department to call me. I am still waiting for that call!