Is it worth it for me to seek money from my employer for retaliation?

I was repeatedly being harassed by my supervisor at my former employer (an insurance company). After I complained to management following the procedures provided in their "Harassment Avoidance" handbook, I was sent a "Written Warning" which contained false statements about me. Later, I was told that my regular pay increase was being postponed 6 months because of MY "behavior" connected to the incident for which I complained. To me, it was the perfect example of retaliation due to my complaint. I have supporting emails and other documents. I was recently "terminated" from the job, and I need to decided whether I should take the severance package, or try to collect more from them because of their retaliation.