I am not sure what kind of company you are, or what industry you are in so advice does vary.

In my last company, we once were "probed" and our books were opened up, I am guessing to see "where we were at".

Maybe your situation was a probe, maybe an acquisition gone bad - but I wouldn't sweat it too much. Your already steps ahead if they even did try and copy you. Your a startup, your a survivor, and just keep trucking on.

Frustrating and emotional I know. You had your hopes up, and the acquisition didn't go through, but take it as a learning experience and use it as motivation to keep kicking ass.

Best of luck.