One of their employees who was/is based at Carlton Centre collected information from my partner (name, surname & bank details) as she was interested in joining they gym January

One of their employees who was/is based at Carlton Centre collected information from my partner (name, surname & bank details) as she was interested in joining they gym January. He advised her the whole process would be completed when she goes through to the gym as no documentation or contract was signed when the employee collected the details from my partner. She eventually didn't end up going but Carlton Gym started to debit her account. Bare in mind that no contract was signed or entrance tag given to her and she hasn't set foot in the gym to use their service. My partner noticed money was missing from her account and when she inquired with the bank, they advised her Carlton Gym was actually debiting her bank account. How is Carlton Gym debiting monies when a person doesn't have a contractual agreement with them or anything binding my partner to them.