Make sure you have a good mobile signal and your device is not in 'do not disturb' or 'airplane mode'. Both iPhone and Android phones have these settings that will stop notifications from being received.
Double-check that you've allowed Billy to send you notifications. In your phone's settings, verify that you've enabled this feature and that the specific notification style for the Billy app meets your preferences.
For iPhone:
- Open the Settings app
- Tap Notifications
- Scroll down and tap Billy
- Make sure that Allow Notifications is on
- Make sure that Show on Lock Screen is on
- Make sure Alert Style When Unlocked is set to Banners or Alerts
For Android:
- Open the Settings app
- Tap Apps
- Tap Billy
- Select Show notifications
Choose which notifications you'd like to see:
In the Billy app, open up Settings 
and tap Notifications.
On this screen, you'll be able to choose which tasks you would like to receive notifications for.
