Contact somebody from HR of that comapny. Explain the person that it's a life & Death situation for you (in terms of career and future). Tell the person that you can send the 'Ready to print' letter in word format through email and all they need to do is verify it and have a manager sign it. Also tell that you can send the scanned copies of the original offer letter and resignation letter for their verification. Explain them that you are not asking anything wrong but just the experience letter from their organization with detailed job duties and responsibilities. Don't forget to be calm and polite while talking and also to thank them (mention that you heartily appreciate their help!). Anybody with heart will help you!
It worked for me and I got letters from my previous employers in US and India in 2-3 days, even if it was 5-7 years that I left those companies and did not know anybody there.
Good luck!
Leo
[
QUOTE=cookie2001]The problem is that for one of the companies, I am even unable to contact ex- colleagues. I don't have any of their contact info and they have moved to various others parts of the world...This was way back in 1997. All i have is the orginal offer letter and the resgination letters which specify the duration I was there and the capacity I was working in...no details on specific job duties and responsibilites.