My question involves labor and employment law for the state of: Illinois

Divorced 7 years ago, QDRO was done. We were told at the time, and I have a letter from the pension company (Carpenters Pension and Retirement Savings Funds of Illinois) stating that as of June 2009 I'm entitled to receive X amount per month. I called a month previous as I was told to do in order to get the paperwork going. All's fine -until yesterday.

They say "oops, we made a mistake". Since that court judgement, they've discovered they weren't applying the correct guidelines and now I have to wait another 5 years to collect. For 30 years we were told all that was needed for early retirement were 5 credits, now they say 10. There are currently 9. The ex-husband no longer works in the field so earning would mean a job switch/career change, impossible in this employment climate. I live in the same home, same phone number and no one from the plan has attempted to contact me for the 25 years the pension existed.

This amounts to a a 5 digit amount of money I'd be losing out on. Is legal action my only alternative and is there a precedence I can investigate where someone has been successful in recovering funds based on these circumstances?

Thanks!