Virgin Active Glen Arces continuous theft

I am a member at Virgin Active Glen Arces for more than a decade now but what is happening there is completely nonsense. I put my bag in the locker with phone and go shower and when I returned my phone is missing. I know it's my responsibility to have locked it but the fact that it was just me and some lady in there made me livid. There can't be anyone else but her. I go to reception to report it and obviously it's not their problem because I didn't lock. Then I was told that I should have left my valuables in front however this I didn't know until I lost my phone. They admitted that people ***** in the changing rooms but they are not bothered about. I also found out that now they even ***** car keys and take your car while you shower! This can't be normal, something must be done by the club, we go there for many health reasons and they can't be treating this as our problem.