can I file a wrongful termination lawsuit? was fired for performance and misconduct issues. Agency of government said otherwise. Paid me unemployment

Did not file in court. letter from employment offfice, after thei r investigation stated I was not incompetent. Apparently my son had written an e-mail which I knew nothing about and it is my thinking that my firing was a result of this e-mail. The statute of limitation might have expired, but I believe I read somewhere where a case can be pursued, if there was some previously lodged complaint to a government agency. At the time of firing I had just left the hospital and was under the care of a doctor. I got back to work and could not get my salary to buy medication. I filed a grievance with HR. Before the outcome of the griievance, I was fired. During that time, all kinds of negative correspondence were placed on my file. veiled threats, withholding of pay, cutting me off e-mail, emotional and psychological warfare, and suspensions 3 times. In other words,they had no case against me, so they started building a case which they used as evidence to back up their false claims.