So I been having problems with my headphones and I read in one forum to uninstall PulseAudio and install other software, unfortunately, I didn't know that PulseAudio takes control of all the audio properties so after doing that all the audio stopped working. I try to install it again and it seems to works in some way, now my computer has audio but I can't control the audio volume with the keyboards and the volume control doesn't appear anymore in the system tray.

I have installed:

Kubuntu 16.04
KDE Plasma Version 5.8.7
KDE Framework version 5.36.0
Qt Version 5.6.2
Kernel Version 4.4.0-89-generic
OS Type 64-bit

Thanks