Failure to Cancel Contract

Since December 2014, I have been trying to cancel my amazing vouchers contract which is R300 per month. I have been given different reasons why I it could not be done. From being told the staff is on leave since it was December and being told that I have some holidays that I have not claimed and will lose out. I state that I will cut my loses yet my contract continues. The latest was that I was told that I had to pay R600 if I wanted to terminate my contract. What type of company is this??? Why do I need to pay R600? I was sold a service telephonically and I regret this dearly.