Ouch. Startups fail a lot. And no, there’s basically nothing you can do as a small shareholder. Shareholders are last in line when it comes to company failure. Generally, there is nothing left.
Maybe you can add your list of failed companies to the Crowdfunding graveyard thread. It’s 100+ posts long.
I never invest in restaurants. Peter Thiel uses them as an example of an industry to avoid due to its highly competitive nature.