way to confirm Iphone 4 unlocked from existing carrier without swapping S card from new carrier

If you follow the directions, which include restoring the iphone, itunes should display Congratulations Your iphone is now unlocked

Did you receive the message that says "Congratulations! Your phone is now unlocked etc. etc." after completing the restore of your phone?

If so; Then the phone is completely unlocked.

If not; Then the unlock has not completed correctly, in which case you should attempt restoring again, and then failing that, contact ATT to make sure the unlock has fully processed from their end

No I didn't receive the message indicating my phone is unlocked. I have tried contacting AT&T twice already and followed there instructions both time without any luck. I guess I need to keep trying till they get things right on their end. Anything else I can do to ensure AT&T does what they promise ?