Sanlam Reality Hidden costs

I was told at Planet Fitness, that I can join for R 259 a month, if I join Sanlam Reality for an additional R100 a month. I signed up and joined both Planet Fitness and Sanlam Reality last year towards the end of the year. End of February, I am billed R519. Upon enquiry, Sanlam reality says I need to go to the gym 12 times a month to qualify for the discount. This was never disclosed to me during signing up with them and I feel cheated. I feel this should have been pointed out to me when I signed up, they only say it's in the contract. Just like when you buy a car they need to make you aware of hidden costs. This is clearly a way to catch people to get them to join them and then they hide costs in the contract.