I called Verizon customer service 3 times to find out when I was going to lose my NE2 credit and I got 3 different answers. The first gave me a date in July, the second said June and the 3rd said never.
On the day the iphone came out I went into my local store to speak to someone in person about this and get to the bottom of it. I spoke to a division manager who was there for the iphone release and this is what I was told.
You have 6 months from the LAST time you were eligible for an upgrade to use your credit. Not 6 months from when they made the changes. I was available for a NE2 on 8/16/10 so my $100 NE2 credit was going to expire on 2/16/11 which was only a week away at the time.
Since there were no phones that I wanted I used my NE2 to upgrade my wife's line and I'll use her upgrade when a new droid finally arrives that appeals to me.
In my opinion, Verizon really messed up this change by not letting us know exactly when we would lose our credits. I was lucky enough to get the right answer in time but I'm sure many others will not and lose their credit.
My advice to anyone that still has a NE2 is to find out exactly when you were eligible for it and add 6 months to that date so you don't lose it