How to disable Mobile data on your Android:
Turn your device on and select Apps
Now find Settings icon on the screen. It may be present on another page so just swap and look for it.
Under settings, if you are running Android 4.3 or 4.2.2.
Select Data Usage and un-tick Mobile Data.
Now go back to previous screen and select more Networks
Under More Networks un tick Mobile data as shown below.
Now your mobile data should be off