I understrand this will be a tricky one.
So when my app resume after the purchase (but still on pause == true), I can’t do anything except naviguate the web trough the browser.
The only solution I found is to close the browser, and only then, OnApplicationPause(false) is sent by Unity. But I Have to do it manualy, because I can’t detect any event to do it automaticly. Not very user friendly.