Tired of illiterate idiots.
(..blabla...) When you stop writing "wattsap". WhatsApp - then in Russian will be "watsoop".
If before the pronouncement of... dig, then it is watsapp (from application, where you can "o" take)
But! Since the name of the app is a game of words (what's up - watts app - well, how, how to do), then this is more than acceptable.