They don't want to cancel my account?

I'm really disappointed of what they had done, 1 of there employees signed me up to get a Zone Fitness account, while I told him not to activate my account? I realized they were didactic money out of my account, after that I went back to Zone Fitness in Wynberg to tell them I don't want anything to do with there accounts or business and that I want my account to be canceled, they told me if they cancel it I must pay a 25%, I paid the money and now they still tell me that there's still a lot of money outstanding? BUT I WAS NEVER IN ANY ZONE FITNESS IN MY WHOLE LIFE?