Technically, you could sue them and demand salary or even demand from court to form a job contract with you and the company.
But it doesn't make much sens, really... It's nothing fantastic to work for a company after such trial. They can't simply fire you, but they will make your life just as miserable as they can.
You may sue them also to get your money in accordance to minimum wage too.
If you have a supervisor, if you do your job regularily in a workplace, etc etc. it's a
job, even if they say it isn't.
But it rarely happens. People are rather afraid to go to court against companies. And as I've said, it's nothing pleasant to work for a company that was forced by a court to employ you.