Bad Communication and Service MTN

MTN Just decides to continue with upgfrading my contract and claims its a continuaion as per their policy, when I didnt ask for it, further they tell me I didnt cancel why cancel something that has ended ? A sales consultant called me around November and I said I am not interested. Now I have been issued with a statement over double the amount of my orignal debit order MTN cannot expect me to understand their product knowledge.