Had a billing issue with my unlimited plan and had to update credit card details. As soon as I had done that I no longer could select an Unlimited plan via Add Data. So AT&T is very strict about who can select Unlimited and on this occasion required manual intervention before they recognised that I'm elligible for Unlimited. I asked them since iPad 2 is coming whether or not Unlimited follows the sim and the sim can work in another device. It's very likely the the sim won't be compatible with iPad 2 is my guess since AT&T wouldn't want to see iPad 1 customers sell their old iPad and continue to use Unlimited in iPad 2.