sorry, you said you didn't mind making a video.
make a video of your app in action. google wants to see why you want to use the remotemessaging foreground service. if they approve, you will be allowed to publish the app on play. google does not want long-running, background-related apps that affect the battery. in this case, they need to see that the principal purpose of your app is remote messaging and to do this you need to run a foreground service. show them.