Pretty much all US labor/business laws are worthless. There's no enforcement. I've tried many times to deal witht he corrupt employers I've worked for in the home healthcare industry. File your complaint, they notify the company about your complaint, and then they wait at least 6 months before they even look at your case. The company simply says "Oh, ok, we won't do that anymore." and it's over. The investigation is dismissed.
Meanwhile, over the last 6 months your employer has had ample opportunity to retaliate against you and probably fire you or otherwise drive you out of your job meaning that even though they said they wouldn't do that thign to you anymore you no longer work for them so it doesn't matter. They then do it to other people and retract their actions and get rid of the employee each time one of them has the balls to complain.
The agency you reported them to tells you somthing like 'Oh, well sometimes there are just personality conflicts. Call me if there's anything more that pertains to the actual case.'
Not only did you get dragged through the mud and made to look stupid and like you were crying wolf, but now you've lost your job and have a bad reference. Yay.
Even if they did do a proper investigation and find them guilty the only thing those agencies do is give you a letter stating that you have probable cause to sue them yourself in civil court.
BTW, even if your employer were to decide to not pay you for your work the only possible thing you can do is to take it to court on your own and sue them. You'll get nothing but the amount you were supposed to be paid.
It's a no lose situation. Either they don't do what they're supposed to and your put up with it, or you drag yourself through hell and provide your own punishment and all they have to do was what they were supposed to do in the first place.