Unacceptable

I was called by an Agent to join the Gym which he send me the application forms to fill in, and return later the same day an amount of R100 was deducted, I'm now unable to gym because of health issues and when I called the gym and call centre I was told to pay an Amount of R 2015.00 cancellation fee! Why must I pay to cancel services that I haven't even used not even a day! I was not even explained to about the cancellation process nor cooling period??? I want this application cancelled Period!