Why would you need to do anything? You are not an employee when you own stock. They do not compensate you for your time to respond to letters. Stock certificates are made to store in a portfolio in a safe. Businesses may choose to invite participation, but most people do not even look at their stock certificates until they need liquidity. In this case the process of "encheating" stock certificates allows a court to relieve you of your property for an arbitrary remunerance, which in this case was less than the original purchase price in equivalent dollars at the time. The company did not file bankruptcy, they just wanted to go back to private ownership and not share in the profits of their success with the people that invested in them.
So the company does something which is legal for them to do, and you blame the company?
I plead ignorance of the law. I will not myself make the mistake in any business knowing full well that they have no legal obligation to honor their debt. Pirateat40 and scammers everywhere, I salute you for duping people that believe that giving money in exchange for promised prosperity is in any way legally binding. I fully expect a major bitcoin exchange to simply abscond with all funds at some point and have a lawyer find some loophole to allow this with no repercussions. I expect that Bitcoinica and Pirateat40 are also completely unaccountable. I guess I would prefer going back to the day when a man's word and handshake meant something, and that gentlemen resolved their disputes with pistols.