SBK gym is *****

I joined SBK gym (Mall Of Tembisa branch) in June and I never set foot in that gym but they were busy deducting money from my account. I went to the gym to ask why money was being deducted from my account when I haven't used their services they couldn't answer this. So I asked them to cancel my membership, they refused, saying I can only cancel my membership when my contract ends - that time I don't remember signing any contract with the gym because they said they don't have a contract, meaning you can cancel anytime. They are still deducting my money and I don't use their services. All I want is for them to stop deducting money from account and cancel this membership.