If your device doesn't ring nor vibrate, it's possible that the Quiet hours feature is enabled. In order to disable this feature, swipe down from the top of the screen to access the action centre. Tap Expand and tap the Quiet hours icon.
It is very important to update the device's operating system on time as the updates contain fixes to various bugs. If you don't receive a notification about the update, check if one is available manually.
See the don't know how to update my operating system guide if you are not sure how to check for updates manually.
Maybe the vibrator got stuck. A gentle tap on the back of the device should be enough to unstuck it.
If you don’t receive the email in the next 2 minutes please check your junk folder, and add [email protected] to your safe sender list.