Account in arrears

In July i was approached by a sales person in Southgate Mall about the gym. He presented that they are on promotion as they are opening a gym, i told him i am not ready yet to join and he suggested i should fill out the promotion forms once am ready i can just submit my copy of ID at the branch then they will get me an access card. I then thought no thats fair, but later on when he asked for my banking details I had a sense it was a bit ***** so i wrote incorrect banking details. I've then later on started getting smses like this \Your gym account is in arrears. Please contact our accounts dept urgently on *** / email [Email Removed] and quote ref no. D14288BG"i called them to enquire about this and i was told to come to the branch"