My story is very similar to this blog post, but with a different solution: http://consumerist.com/tag/returns-...efective-iphone-3g-is-a-huge-pain-in-the-butt So I bought an 8G iPhone 3G and returned it to exchange for a 16G iPhone 3G because I wanted more space. The problem began when the system recognized me as having used the subsidized price to purchase an 8G iPhone and therefore wanted me to pay the unsubsidized price for the 16G ($499). This occurs when the Apple Store employee enters your info as an "existing AT&T customer." Obviously I did not want to pay the unsubsidized price, so this is what happened next. The Apple Store employee and I proceeded to create a whole new AT&T account with a new number for my 16G (start off as "new customer to AT&T" instead of "existing customer"). That worked out fine with me purchasing the new 16G iPhone 3G at the subsidized price (paid the difference between 16G & 8G + NO restocking fee - got lucky there ). So at this point, I had 2 accounts opened with AT&T, one with 8G & the old number I want, and one with 16G & the new random number they assigned me. After I got my new phone, I called up AT&T to get my old number back (still with the old 8G account) and to cancel the old account. It turns out that it's not feasible to do this because you can't just transfer a number from one account to another one leaving one account numberless (guess it makes sense). So after talking to a manager for well over an hour, what she did was to replace the iPhone information on my old 8G account with the new 16G info (she wanted the IMEI number written on the box), then I had to get a new SIM card which she entered into the old account info also, and then canceled the NEW account that I just made with 16G iPhone. So that solved all my problems. If you plan on doing a similar thing, just ask them to repeat the steps above and you should be good. I don't want anyone going through this ordeal like I did. It was long, torturous and frustrating but at least everything worked out in the end. And after the experience, I strongly believe that Mac Geniuses have no idea how to handle any of this account issue. They're nice and all, but they don't know squadoosh (understandable, however). To be fair to them, AT&T customer service reps don't know any better. They'll just tell you "it's not possible" or something like that. So another advice is to call AT&T and to speak with a manager if you have a complicated issue like I did. Good luck!