Company is close down in 2010 - How will the background verification be conducted?

My company is close down in 2010. I was working as trainee which is almost 7.5 years before . I used to get salary in cash so i dont have bankstatement or Pf statement or form 16. Now i have a offer from Accenture. How will the background verification be conducted? Should i accept the offer?
I have already informed the talent coach. But she says you reject the offer.
What should i do? Please help

Tell them the facts, give a try mustering all available channels. Why don't you get atleast a reference letter from your erstwhile colleagues, Heads, reference letters etc. I can't predict what type of documents could satisfy the requirement of Accenture. Don't you have any document to prove having worked there. Offer letter, ID card, entry pass. Nothing wrong, do whatever you could do. Don't ever reject on your own.