Why can't I see my data usage on the LG G3?

[fay68]

This phone has an AT&T GoPhone sim card in it. I pull down notifications and click data usage and it says: 'Carrier data accounting may differ from your phone'

 

[B. Diddy]

Welcome to Android Central! That's a standard disclaimer. But are you saying that it doesn't show you how much data it's been using at all?