Just a heads up... Guys who have returned their OPOs need not necessarily wait for an invite.
Just contact Amazon cc, & tell them that you've returned the phone but you'd still like an invite to purchase another. They are acceding to such requests atm. Lots of guys on the OPO forums have (re-)gotten invites this way.
Just try writing 'em a mail asking politely why can't you get one when your friend/s have?I had called Amazon yesterday & requested the same, they rejected it saying I can't get an invite as I had mentioned Yellow Tint as d fault in the phone..
The rep mentioned that they are not giving invites for yellow tint issue, as they received some 60,000 devices back because of this issue & OnePlus One says that this is the feature of the phone..