At least now you can take the loss on your taxes. That's the only reason I can see to sell at this price unless you have millions of shares.
As for a shareholder suit, selling doesn't remove you from being defrauded and compensated, but I would be stunned and amazed if there even was a lawsuit for several reasons:
a) the odds of winning are very small. Unless you can prove outright lies, "being wildly optimistic" isn't going to cut it.
b) creditors would have a much stronger "fraud" claim and are owed a ton of money
c) Where's any payment going to come from? The company has nothing, and the management likely not much more.
I think your best recovery will be from the IRS. Hopefully you have some gains to offset.
If you feel you were misled into buying shares by the company or anyone else, your best recourse is to contact the SEC and file a complaint. It won't get you your money back, but it will send a message that this behavior is not OK and perhaps result in those who did perpetrate any fraud being barred from doing it again.
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