Volume down key is no more working and i still in safe mode on my s4 gt-i9505

Hello !!
I have a samsung galaxy S4 GT-I9505
since my Lollipop 5.0.1 update, the volume key (-) is not working. Now my phone turn in to safe mode and i don't know how to deal with this. I tried everything.
Need help please !!
:D:D:D:D:D