Basic-Fit complaint: Contract Fraud

I visited Antibes for 1 week on holiday and wanted to sign up to the gym. The member of staff working advised me that as I was on holiday the shortest membership they offer is one month, which I was fine with and he helped me to set it up on my phone as it was quite confusing and that was the end of it. However, this was not the case. I have just received an email from a French debt recovery firm to collect debt that i owe. The employee has signed me up to a 52 week contract. I live in London, i would not sign up for a 52 week contract this is absurd. I have emailed basic fit multiple times to try and get this resolved and i am met with completely useless replies, disregarding anything i am saying and telling me to pay. I have been completely misled and put my trust in their staff to offer a helping hand. this is completely unfair and basic fit have been completely useless.