If the keypad screen is off you can activate it up by pressing the "i" button. The keypad will not activate if the battery is flat. If you have electricity, plug the keypad in and the keypad will activate.
If you do not have electricity, replace the battery or plug the keypad in at your nearest neighbour in the same block and enter your token.
The token is linked to your meter so the credit will only be loaded on your meter and not on your neighbour's meter.