Hi guys, I'm bought an AT&T iPhone on contract a few weeks ago and I found out that I have to go overseas in December. Of course AT&T won't unlock it for me. However, I keep on seeing Craigslist and eBay ads advertising iPhone factory unlock services in the range of $20 to $50. They are extremely vague on how they are accomplishing the unlock, something about they have ways to whitelist my imei on Apple servers. Anyone here ever use one of those Craigslist/eBay unlock services?