How do i get my w-2 forms from IRS 1994 to prove i paid into an annuity and dispute it with the company i worked for

I worked and paid into an annuity . The company has since changed from consrtruc tion  to real estate and says the money has been distributed . I recently filed a SSI claim and was notified that there was money owed me However i need to show that i paid into the fund in order to dispute this