I'm sorry to hear that happend to you. Leaving your battery out for serveal minutes will not accomplish ANYTHING. It's a factory defect. The Torch I got on launch day 8/12 eventually lost functions on the physical keyboard (A, S, O, L, P). I returned the phone to the ATT store and they gave me a new one.
THIS IS A DEFECT, return that one and get a new one!
Resetting to defaults or doing a BP will not remove / reverse the unlock. Doing any of the above also will not fix the issue. WCH is correct, return the device. I am pretty sure you did not purchase the device from an AT&T dealer or it would have came locked. You do not say explicitly that it came that way but you do imply that. Return it to the place of purchase.
Posted from my CrackBerry at wapforums.crackberry.com