Billing for services never ordered or approved

Since I connected my ADSL line (for internet purposes only), Telkom have tried to bill me for a Telkom Evening W/Ender Plan which relates to a voice telephone. I have never requested this and don't even own a landline telephone. After several attempts to get this removed from my monthly bill, it still appears ever month and I keep getting told that i short pay and owe Telkom money. They never return my calls, respond to disputes logged through their online system and haven't made any attempts to fix this.