I've had this problem for a few days now. I'll be using 3G data for a few minutes. I'll notice a change in speed, then a sudden drop in connection. It still shows 3G with four/five bars on the top area. I put it in airplane mode then back. It will show four bars and AT&T without the 3G. Internet still won't work. Then, the bars will disappear all together and show "No Service". After waiting 10-15 minutes, it comes back again. What is going on? It's a very annoying problem, and I hate unreliable service. Are there any fixes for this?