Monitor Outbound Connections
Most android devices now have monitors built within their software. I'm not familiar with the G4 so I can't say for certain it has the feature but my Samsung S5 does so I can lead you to it based off of that.

If you go to Settings there may be an item labeled "Data Usage". If not, look for "Mobile Data" and see if its in there. Within there it will show what apps are using data and how much data they're using. It's a great way to monitor your device.