Got denied authorship on paper; neither university nor publisher feel responsible
You probably inclined to think that "there’s nothing anyone can do" is equivalent to "I do not want to do anything". I want to provide an alternative way of thinking. Think about it as "There’s nothing anyone can do constructively, i.e. to your benefit". One can do many things here, but will they be useful to you in some way? Punishing someone gives only a temporary satisfaction. A possible course of action along this line would be that an erratum is written to this article stating: 


  We acknowledge J LecC for insightful comments to this paper.


But does it bring anything? Your publication list nor your h-index will not grow because of this... Therefore, cynically speaking, just be happy in your new lab.