Termination with a lie/Retaliation/Unfair work practices.

I was terminated and on my termination paperwork it says that I "endangered the patients, visitors, employees and the facility of Children's Medical Center". I have paperwork that proves that nothing I did or did not do endangered or would have endangered anyone. I believe they were retaliating because I told them I would no longer work in a position for free. When a co-worker quit, instead of re-opening the position right away, I was asked to pick up the slack while they used the budget for that position for another, and then they would open the position. I did the work and was recognized by my superiors, my co-workers, and the state as being in that position. I was the only one asked to do this, and the only one doing it. Every other person who is/has been in that position was paid for it. I did it for over a year with no pay. I continued to ask them to re-open the position. I finally told them I would not do it for free anymore. They re-opened it, then I got fired.