Have question about legal issues and employment?

I was hit with slander 2 years ago on a cruiseship where I was a fill in/sub vocalist for the bands on there, but I was never hired by the cruise company itself. I auditioned for their sister cruise ship next store, and actually got the gig, the people loved me, and I filled out an application (i never did 2 years ago) but one of the managers recognized me when I auditioned. So a day later I get a call saying I was non eligible for rehire....how is that so, when I never worked for the company itself 2 years ago and never filled an application back then?. I would like to take this matter to court because 2 years ago, with the whole slander thing (it was absolutely horrid), slightly damaged my reputation as a vocalist and it put a damper on my income...and I was depressed for almost a year.. I am a professional person/musician. I do have many references that state this..I am also a music major at college. What should I do?