I worked for a company that did exactly the same thing. I didn't take them to court. They jerked around my friends who kept working there for years. They wouldn't pay them for months, fire them, rehire them with promises of giving them their backpay... all sorts of financial abuse. My friends were on the "creative" side of things, so they didn't have as many other options for employment, which is why they took the abuse. About a year after I quit I met someone who had worked with the CEO a long time ago, and said pre-startup the CEO was notorious for not paying bills, stiffing employees, was in estate lawsuits with his own sister, ex-wife and so on.

You should take them to court. Part of being a CEO/founder is taking care of your people. If you don't do that, you're really just using them.