Maybe you should give him more than one hour to get back to you, he could be sleeping or at work for all that we know...
And just maybe he doesn't want to publish his e-mail either, as I know the spambots will just love it.
That's why I stopped publishing on Google Play, they require developers list a contact email on the game page and ten spam years later, after getting suckered into wasting on some crappy publishers and mobile ad networks, I had enough.