Gym contract

I had a contract at Virgin Active The Sanctuary in Strand. I had to move to I called in to cancel my gym. I asked the gentleman to answered the phone how much my cancelation fee would be he said (the amount) and then he ask would I like to make it a monthly payment or as a deposit order for once off I said once off please. I ask would that month I have canceled my contract still be added he said " No it would be just the cancelation ".So that month they deducted the amount from my account. Know Virgin Active reported me to MBD for not paying but I have payed my account to full.