Stolen Money?

I work at a lounge/sushi bar/restaurant/bar in downtown Dearborn. It's a family owned business and I have been working there for almost 14 months. I work hard and I work a lot, but the pay off is good. I make more money there than I do anywhere else. Though, the workers put up with a lot of bull$h!+, and there really isn't any way for us to fight it. For example, I worked New Years Eve, it was kind of a dud. There was a pre-set menu and charge per person. Some people payed ahead of time, and some people were paying at the door, or had made arrangements with management on later payments. At the end of the night, it ended up being that the servers weren't given gratuity for 27 people at $115 each, that's about 31 hundred dollars, and that's about 775 dollars of gratuity we weren't given that night, but promised to in full in the next couple of days. A few days later, my manager tells us we aren't getting payed for it because we were drinking on the job. It's true that some people were, but also true that many of us weren't, including me. Now, how do you fight that? There's no higher, boss, they are the only people in charge. And also what am I supposed to do, it's not like I can quit, even with getting ripped off that much, I still make good money there. How do you fight that? How do you fix that?