@Snehathomas - My new letter went few months later (say 3-4), but my company was a MNC very well known globally, i think that decreased the risk of rejection as they do a generic online search of the company name, address, postal code etc. My offer letter was very detailed as well.
Everything is same - under process.
It becomes 'approved' after COPR.
I think the complexity of job role, closeness to NOC and public visibility of the organisation you worked in plays a role. But there have been many cases of people working in startups that have been shut now have got their PR... I wonder if they gave other paperwork that the company existed once upon a time...
Just depends on how much proof you can give it seems to me.
Best of luck & keep asking them if they need anything else.