Hello, I just updated from 5.1.1 to 6.1 on my iPhone 4. I was under the impression that FaceTime would be available over cellular data on iOS 6.x and above. I have tried it multiple times to make a FaceTime call but I get the same error telling me to connect to a wifi network. I am currently on 2GB/month plan which I signed up for back during the launch of the iPhone 4. Any ideas why FaceTime is not working? Thanks.