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There IS a way to get it back, but you need a new regular sized never been used before sim and a original 2G iPhone.

Restore the 2G iPhone and then place the sim in it. Once that is done, connect the phone to iTunes and when asked, you are replacing your current phone with the original iPhone. Select your unlimited plan +200 SMS or however many you need and wait as the phone activates.

You now have unlimited data and now place that sim in your 3G or 3GS phone.

If you want to use it in a 4, you need a Micro Sim and a simple phone to AT&T to have the sim activated so that you can now use it in your 4.
 
So after some complaints that AT&T never sent out an email to people telling them that there won't be unlimited anymore, I was directed to an upper level support and I was able to get unlimited back.

Wooha!
 
Getting unlimied back

yeah just like the other guy said, you have to get a iphone 2nd generation and new sim...unlimited is offered thru that and then just switch it to your 3GS...thats the only loophole ive seen...
 
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