What To Do If BG Verification Failed After 2 Yrs

Hi Experts,
I am working in software company since 2 years.Intially when i joined this company i cleared the BG verification two times.After 2 years my present employer done BG again and found that my previous IT employer is not responding/existing.Later i came to know that 5 months back previous employer is closed due recession.I said same thing to HR but they are not convinced and they asking for form16 /incorporation letter of previous employer/bank statement(in which my salary used to credit)
I worked with previous IT employer as on contract pay role,its employee strength was arround 60 employees.I used to get salary as cash and so no form 16 issued to me.
Please guide me how to get the Incorporation letter of previous employer,which govt authority i hve to approach?
Please guide me what to do now.
Thanks

Dear Friend,
I am quite surprised with the fact that your current company doing BG third time, where as many companies don't do even once. anyways, if you have copy of your past 2 time BG, then give that to them and request to consider the same. If not, check if you can give declaration stating your salary and experience and give reference of any one senior executive officers of your previous company as contact to verify. If all these things fail, talk to someone senior in your company and explain your situation and take their help.
Ashok