When you run out of data on an iPad, you will see a pop-up asking you if you would like to buy more data. Don't worry if you see a blank screen after clicking "Buy" - this is expected behaviour.
If you would like to top up, please purchase data by logging into your AOW account and topping up as usual.
Once your data has been used up, you will receive a popup notification to inform you that you are no longer connected to the cellular network (see below).
Once you press OK, you will be prompted to top up (see below).
Clicking "Now" will prompt the pop-up below to appear.
Click the home button to remove the pop-up and return to your home screen.