I'd be wary of any of these companies who offer large rebates. You have to figure that the way they make their money is by having as few people as possible cash in the rebates. And by spending the absolute minimum on stuff like support and order fulfillment.
So, if you go with a company like Inphonic/Wirefly or Simply Cells, you can count on no support and having to jump through hoops to cash in any rebates they offer.
I placed an order on 6/17/04 which was the beginning of a nightmare! I could not get accurate inforamtion about my order and their customer service hides behind email because I was unable to contact anyone by telephone. I was told on one occasion(via email) that my order had been shipped but when I attempted to check on the shipping status I was informed that my order was still being processed. Finally, after three weeks I received the telephone with a congratulatory letter welcoming me as a customer and informing me of my new wireless telephone number with AT&T but by then I had decided to cancel my order and return the phone. I followed their instructions to return the phone and when I called AT&T to cancel the service I was informed that a number had not been activated for me and the number Wirefly/Inphonic told me was mine, was actually assigned to someone else and in use. When I called to get a return authorization I finally got to speak with someone in customer service who wanted to know why I wanted to return the phone. He didn't seem to be too concerned when I outlined the problems I had experienced.

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