Some buttons do not work

[Kayabey]

Hi everyone.

I bought a new car. 2013 model pegeuot partner tepee zenith. But some buttons on the radio don't work.

For example, I can increase the volume but I can't decrease it.
For example, the round button in the middle turns left and right but when I press it, it doesn't do anything.
For example, the numbered buttons for the radio "1,2,3,4,5,6" don't work at all.
And I can't get into the menu.

There is a camera mounted on the trunk door of the car and the camera doesn't work either.

I read many topics on the forum. I think my problem is software related. Or if it's something else, please let me know.
How can I update the software? Is it possible to update the stereo without removing it? Or do I need to do something else?

I'm in Turkey. And the car mechanics here don't know this stereo very well. Can I do it myself?

Thank you in advance for your help.

Software Version: RNEG2.86.B.1