Ugh.... I had to deal with similar crap.

I tried to return after 3 months without pay or they were going to fire me. I lasted 2 and half days.

However, my neurologist felt that my relapse had a lot to do with the stress my employer put me under in regards to my return, (my boss neglected to inform me he was missing documentation he needed for me to return to work adn then threatened to not pay me)

Anyway, after many arguments with my state's unemployment program, I was able to provide documentation as to what happened and that my boss had caused undue stress with exacerbated my condition, so I was at least able to file for unemployment benefits until those ran out.

But Mark is right, document everything! If you are unable, have a family member or friend you trust help you keep track of all the communication that occurs between you adn your employer/HR.