Been trying to end terminate my contract to no ava

I've been calling and emailing Telkom since January 2016. My mobile contract has ended and they're still deducting my monthly payment to this day. Last communication was 16 February 2016 where they said their retention department would contact me. It is already 28 February, I haven't heard from them at all and I'm still paying. They are absolutely useless and rude when communicating with me. They're wasting my time and money. All I want is to cancel my contract as it has already ended. Why am I still paying??