If you are serious about building a case against this company, start a journal and keep track of incident dates, names of everyone involved, and contact info for ex-employees.

Isolated incidents are usually not enough to get the attention of a the labor department. Systematic abuse is what needs to be established.

You might also want to talk to a law professor and students. They might help you develop a case for free.

Keep in mind that something like this will consume your life as you are going against a corporation with corporation money and resources. If the company is as cheap with their workers as you say, they may not have a huge war chest. However, they have more than you. When your role in any kind of investigation becomes known be prepared to be a target. Even if you have lawyers on your side, they will want to vet you and find out what kind of axe you have to grind with the company. If you are dealing with people in that company that don't mind breaking the law, how far do you think they will go to keep it under wraps?

I'm not trying to discourage you. Just enter into this kind of fight knowing what you are dealing with. Maybe Sam understands the cost/benefit of the fight better than you. Maybe he simply doesn't have the resources to deal with it and would rather restart fresh. That is a individual personal decision. You seem concerned that justice is done for employees and that the corporation that is stopped from this behavior. I applaud you for that. It's admirable.

It sounds like a horrible place to work. I would get out of there as soon as possible. However, if you want to follow through with seeing justice done get some form of legal help now. Look up information on corporate whistleblowers. A whistleblower is basically a rogue undercover spy working towards their own mission goals. How they did what they did. Why they did it. What was the result of their actions for the company? What was the impact to their personal lives and career?

Do not enter into this lightly. Do not enter into this thinking anyone is going to give you a reward it even a thank you. Enter into this because you are dedicated to seeing justice served and protection the anonymous people who would continue to have been abused by this company's abuse.

And stop posting about it publicly!