Unfortunately the phone in question is a AT&T specific phone for the time being, unfortunately until that changes the only options are to return the device if you have had it less than 14 days or find a outside source that will cost you to have the device unlocked.
I completely feel your pain. I am furious at AT&T's customer service. I recently purchased an HTC One X+ with a new contract and the representative explicitly told me that I will be able to begin the suspended rate ($10/month) whenever I wanted (for a maximum of 6 months). 14 days later I tried to do it and the Customer Service representative informed me that I would have to have 6 months of service running for me to be allowed to get the suspended rate. They blew off my protests by saying the representative wouldn't have said that since it's not the policy. I kept insisting they did and they basically said not our problem. I cannot believe the degree of inconsistency that AT&T has displayed and will be cancelling my two-year contract.