HELP! AT&T Data Overage? What's that mean?

Hmm, that's weird. I'm with AT&T, and online, it says unlimited messaging includes IM, texting, and picture messaging. If you don't have unlimited messaging (haha nvm .. just saw that you have unlimited, my bad) .. that's probably the issue and data overage can cost a ton - trust me. AT&T charges $0.01 for every KB you use. Maybe you accidentally went into the internet a few times? My stepbro is supposed to have internet not accessible to him, but yet it says he's used some. Good luck.