Discharge Question

I was told over the Christmas holiday that my job was being eliminated because of organizational changes. I was an Admin Asst, and whenever I would ask for a job description I was told to refer to the receptionist job description already on file. My manager and I didn't get along and she tried to have me terminated on my performance but failed on many occasions. She also harrassed me, and violated company policy. She denied me training when I asked repeatedly. I have documentation of everything and repeatedly went to HR about her. Nothing was ever done. When I was on FMLA they brought in a temp. Two months before I was let go they brought the temp back (who my boss wanted to give my job to). She told me this when I came back to work. They put her (temp) in another dept, laid me off end of Dec 2016. The temp was offered a receptionist position aka my position a few days ago. My question is do I have a case if they post my job that laid me off because they said my job was elimated? What is the time trance on when they can Los my position? I'm claiming discrimination for me losing my job when there is work available. I receiving unemployment and I was offered no other position in my company (production, quality, etc) I have the letter stating the lay off from my company as well. What are my rights?