I'm on an old AT&T family plan. I was planning on getting the iphone at an AT&T store, but it looks like it's faster getting it at the apple store (plus I have a chance to win an apple gift card). I had already talked with AT&T and they told me I could keep my voice and text messaging plans and just add the $30 data plan. If I go to the apple store, would they know to just add the data plan? Do they have access to your account like the AT&T stores do? I'm worried they'll screw up, give me a completely new plan, get rid of my text plan and make me choose a new text plan. 