So, I purchased the 920 yesterday to replace a lost iPhone 5 and I now can't receive iMessages from iPhone users. I can send to them but can't receive back. No issue with non-iPhone users. AT&T support has informed me that this is an iMessage issue and just sends me to the Apple support folks.
Is there anyway to resolve this?
The ACTUAL fix for this was for YOU to log out of/turn off iMessage on your phone number before you stopped using your iPhone. You told the iMessage server your number was logged in to iMessage, so when some other iUser messages you, it tries to use iMessage. If you forgot to do this, then having your friends delete/readd you does clear it for each of them. You're kinda screwed since you lost your iPhone, but if someone is migrating from iOS to WP8, that's all they need to do.
Edit: from the interwebs... if you have access to a Mac, you can still fix it this way
"I know this question was a while back but I figured I'ld answer anyway.
Launch the Message app from your mac
Log into the account of the person recieving the unwanted messages
On the top right corner by the apple logo, it should say "Messages"
Click on "Messages"
Click on "Preferences"
Click on the "Accounts" tab
Click on your accounts and see which ones have numbers that are linked to them (you can see those numbers on the right side)
Uncheck the number in which you no longer want to recieve messages from
There you go!"
So, maybe you can hunt down a mac and do that?