Wrongful termination and denial of vacation pay

This is a family business. I was terminated for alleged poor performance recently. I worked there for 10-1/2 months. I am 46 years old and was replaced by their 30 year old daughter, who just had a baby and brings her into work everyday. My former employer stated that I had to sign a release in order to receive "severance" checks and promise not to "sue" them in any state or federal court for violation of the ADEA. Based upon my current pay stubs they "assumed" I would accept this severance and decline my rights to speak to an attorney. My paystub shows that I accrued 80 hours of vacation of which I never received those checks, also my pay checks show that I earned income I never received. What can I do to receive those vacation checks and do I have a case for wrongful termination because the job I was hired to perform was stopped in December because I was told to work in their warehouse performing physical inventory with all men, while their daughters sat in the office and were not required to do the same tasks as I did. They are 28 and 30. I also have multiple sclerosis. What agencies should I go to for help?