Unreasonable cancelation fee

I signed up for a membership with Gym company and never used their facilities or even went to their facilities i don't even have a membership card and never registered my fingers on their system i called them today to cancel the membership and i was told i need to pay R3512.40 but what am i paying for since i never finalized my membership with them i feel rather exploited by this company as the reason I am canceling is because i got a salary reduction due to covid 19 and i am paying rent and my sisters school fees and I currently can't afford the gym fee, I also let them know if the could hold my account up until my finances are back to normal then I would activate it again. How would I be able to pay 3512 .40 if I can't pay 400 nevertheless I have never used or been to your facilities. Only if I knew