Telkom making me pay for a line i haven't used for over five months.

I have been trying to cancel my phone line since December with absolutely no luck. Every month they send me a new statement and expect me to pay for a line that i haven used in over five months. Every time i call them they tell me that it is in the process of being cancelled or have an excuse as in the system has been changed and there is a back log that they need to attend to first. I have never dealt with such a pathetically useless company in my life and wish i could give them a no star rating.