AT&T took my IMEI but didnt give unlock code. Can I unlock the same RAZR or can

[uzee]

they block based on IMEI ? I have an old ATT(blue) account and recently got a new Cingular (Orange) Razr from a friend. I thought it would automatically work, but it didn't. I called ATT and after 2 hrs they told me that even if they give me the "Unlock code/Subsidy password" the new phone wouldn't work because its "made" for the new Orange network. They also took my IMEI by first saying that they can give me the code.
Now, my question is, even if I get it unlocked from a shop or Ebay, would it still work? or because ATT now has my IMEI, they can permanently lock that device from connecting to their network?
Secondly, what would be a good source to unlock it myself...?
Thanks