My Open Source Dilema

I was terminated from a company that I worked day and night for for about 5 years.  During the last 2 years of that time, I created a simple web framework and contributed it to open source.  We had always used open source, so it was high time we became a contributor!  Recently I found out that they have removed all of the licenses from the files (GPL and MIT), gave it a silly name, and have the intention of marketing it as a product.  What should I do?  I am trying to get past the fact that I am upset that I was terminated — that pissed me off — but the fact that they are taking credit for my work and making it proprietary is really bothering me!  What should I do?