I upgraded from an iPhone 4 with a grandfathered unlimited data and unlimited messaging. Upon activating my iPhone, I noticed I had no data. I called AT&T. At first, they said I did not activate it properly. Because I was unlimited data, I needed to call in to activate my phone. I called that bull and said I did the iTunes activation as their website said. Next they tried to tell me that I did not transfer my plan from my old phone to my new phone. I again called that bull. How can I have an iPhone without a data plan? And if it did not transfer then why did my voice plan? In the end I ended up getting a temporary 3gb data plan and having them throw unlimited messaging back on while "they look in to it". I am not impressed.