Sometime there may be a delay form Google side, so you can receive the same after a time interval.
We have recently updated our sample application with following enhancements.
You will be able to send extra data as Json format.
You can also configure for No notification in Bar if application is opened.
It will be able to show Notification if application is fully closed.
Please download latest Unity Push Sample.
Let me know if you have any queries regarding this.