Over the last week or so my iPhone 4S has been completely dropping out of AT&T's data network. I've only had about 500mb transfer thus far on my billing cycle and I'm still grandfathered in from the unlimited plan. The strange thing is that it still displays full bars and the 4G symbol next to them. The spinning data will still spins when it's doing all it's work, but when using the "Speedtest.net" app I see less than 0.5 download and basically a flat line for upload. Is it time to make a genius bar appointment? Anyone know of any issues?