While on a 6 month maternity leave sponsored in whole by my company I got a call from my manager that my position was eliminated. While on maternity my company merged with another firm. There was some restructuring as part of the merger but it did not affect my department except that there was one person laid off and my position was eliminated. Before leaving on my maternity leave I trained a temp employee and my manager to perform my duties in my absence. Eventhough I was told that my position was eliminated all the fuctions of my job are still being performed most probably by the temp and defi by my manager. I was offered 2 month severance and possibly 3 month severance if I sign the document stating that I will not sue the company. Do I have a case?

I'm not seeing a slam dunk case. Being on maternity leave does not protect you from adverse actions that would have taken place had you not been on leave. If you've been out for six months, the employer held your job far longer than the 12 weeks it was legally required to by law. And, a position being eliminated doesn't mean that the functions of the position will no longer be done -- it means that head count is being reduced.