Taking back the question a step (or two) back, I had lost the data plan before the switch to my current iphone5. I had it with a previous iphone but it was removed at some point. I never questioned my bill because it was autopay and I never hit over the 2GB limit.
I think I lost it somewhere when I got my 4->4s. I think I asked them once about it and I was told the unlimited data can no longer be kept when I upgraded? Don't remember anymore. But today, the guy at AT&T said it was because my phone was bought from Apple.
I only started to ask about it when a friend at work told me he still had his unlimited and got his iphone5. When I bought my iphone5, no longer had my unlimited. But if it was removed before in error, I would like to figure out who to talk to being the guy at the AT&T store couldn't help me. I guess I would have to call at&t, which should be a fun.