I think I screwed up the APN and I don't know how to fix it. What is the AT&T APN? Also the Sim place is also empty. I have a 32GB with WiFi and 3G. WiFi works fine but I'm confused with this APN - Do I leave it empty? I've been trying for a week to get this going. I have a data account with ATT and they gave me a data number that looks like a phone number.