Booking System not working, S**** it totally

Today i booked and got confirmation of Cycle Spirit for 17h30, I get to gym and the class is full, all bicycles occupied, I tell the lady I have a booking and she just smile and walk away, I go to one of those bicyle outside class as soon as I put my water bottle and towel they telling me they taking that bicycle as well for someone in class. What is the point of booking if people who did not book arrive earlier and occupy bicycles? the system is not working then, why am I paying? why are people who did not book allowed to occupy bicyles without proof? The manager told me to keep on booking, question is why? waste my diesel and time for a system not working? I am disappointed with this, super disappointed.