Same as well happened to me.  I had 20 shares, looks like the guy just stole the bitcoins, instead of the buyback @ 150% trading value like stated in his stock info. 
Also cryptostocks support is fucking useless on help for it, so I'll be liquidating and removing all my bitcoin from the site with absolutely no security or user protection.

Hopefully the GDICE owner does the right thing and gives our money back.