Contract Nightmare

I have a huge problem, my number has been suspended, I have been trying to cancel my contract also. According to the collections department, I have also missed payments, the contract can't be cancelled while they are missed payments. I have requested for the contract to to be cancelled months ago, so that no contract resources are given to me by end of June, to my surprise, it wasn't done. I asked for the matter to be escalated to the manager of the agent I spoke too, who was so rude. Yet it wasn't, instead my call was cut off by her. All I want to is for the contract to be cancelled and also note that I will not pay what I'm not liable for!!! I must say and thank Morena and Onkemetsi for their pathetic service