In most cases, the handset has turned itself off because the battery is dead or because it has a power saver mode which turns the screen off until you touch a button on the handset.

If you think the handset might not be working as the battery is dead, try to charge the phone as normal or test an alternative charger to make sure this isn't causing the issue. 

We suggest contacting the manufacturer of your handset for further assistance if this hasn't worked so they can check if there is an issue with the handset.