Will not terminate my contract

I've been on contract with MTN for four years. My latest contract term was about to end so I figured I wanted to terminate rather than upgrade. So went to my nearest shop at the time, Newtown Junction Mall, where I was told how to go about closing my account with MTN.<br> <br> I submitted an ID copy and letter at MTN Newtown Junction stating that I'd like to port to Prepaid (as directed by the sales rep) because my contract term came to an end in early November. I did not get any acknowledgement or confirmation from MTN. Is that normal? How do I know that my contract has been cancelled? <br> <br> So, early December 2015 I messaged MTN on twitter and I was told they would look into it. A few days pass..nothing still. So I message again and the response I get is that they would notify the Contracts team and they will call me soon. Not a single word from anyone.<br> <br> It is now mid January 2016 and I am still receiving invoices from MTN!! I just don't understand why I am being held hostage and forced to pay for something I do not want anymore. The reason I went to the shop to inquire about what I'd need to do to terminate this contract was to avoid this exact situation. It's very frustrating!