Hi Dammit, I am sorry for you. These locks can be expensive, that's a real pain. Having said that, from a legal standpoint, you had left something on a private property, it probably didn't have your name/number on it, you had no written authorisation to leave it there so technically, you are not in a good place to try and recover that cost. In this scenario, I am not even sure they would have had to tell anyone about cuting those locks tbh. Imagine someone attaches a lock on one of the gutters of your house, well, you'd probably be entitled to remove it at your convenience. Prob best to try and have a smooth conversation with the manager of the gym and propose something like to split cost for a new lock or something. Good luck with that.