daynamcfly

I was employed with TWA from 1977 -2003. My pension from 1977-1999, which was the date American Airlines aquired TWA, is held by the PBGC. They claim to not have any record of me in their data base. They requested TAX returns from 1999 and before. I have been on the IRS website and they only go back to 2005. How do I prove employment? I provided letters of my 10 and 20 year employment but they want IRS proof.