Alarm clock

Hi Angelika, I have that phone since one week and had the same problem = awoke half an hour before the real hour O.O

I finally found what it comes from that afternoon ! 

What you have to do is go in the phone settings then in Sound (at least, it appears in French - I am French - as " sound " and from there, go to " notif sound by default " . Enter and choose : NO sound.

After doing so, I've checked many times and it was ok. And, don't worry, it is only the notifications sounds you'll remove = not the clock sound ;)