Non-Contract Gym Cancelation Fee

Hi, for context I’m living in England and recently (12th August) cancelled my Gym membership, I’ve been told due to the 30 day cancellation period I will be charged for September and will have access to the gym until 01/10/2024. My question is, if I’ve never signed a contact, do I legally have to pay this or can I remove the direct debit? I understand it’s company policy but I never signed any paperwork to agree to this. I’m just interested in how this works. It’s not the end of the world if I have to pay it, I’m just wondering if I legally have to, as this feels a bit cheeky to me.