Have you tried just using plain sms?So I tried to test out messaging with Facebook messenger to see how it would be if I were to get the S8.
Facebook messenger is used just about by everyone on my contact list so that was good.
Problem is people simply dont reply when i tried to message them...I know they were available because I sent them an imessage and they responded.
So this makes it harder for me thats for sure. Im not sure what the issue is, maybe the notification is set to off as default in messenger.