I don't understand how people are able to cancel their AT&T order. I have tried multiple times.
I preordered at an AT&T store. They told me about the 7-14 day wait, but was told that it would be the same wait if I ordered from any other place. When I got home, I called Apple to see about this and was told that if I ordered from them, I would have it on the 19th. So I tried to order one through Apple and was told that my order could not be completed. And I'm guess it is because I had already preordered through AT&T.
So I rushed back to AT&T and tried to cancel it, but was told I could not. I even called AT&T customer service and talked to someone who then called someone at the same store I had preordered it from to try and see if they would cancel it. But even she had no luck.