If you want to avoid using data, you need to deactivate mobile data on your mobile phone. Once done, you can only make voice calls, send SMS and use applications that don't require an internet connection.
Turn mobile data on or off
Return to the home screen
Slide your finger down the display starting from the top edge of your mobile phone.
Tap the mobile data icon to turn the function on or off.
If you turn on mobile data:
Tap OK to confirm.
Tap the home icon to return to the home screen.
*Please refer to the Sony website for more information or further support.*