Stereo not working

[Mka306]

I have a split screen audio and climate unit, the climate part top half all works fine but the bottom half, the stereo no buttons work what so ever, the screen is on and it's displaying the time and a radio station, I can turn the volume up or down but I can't turn it off unless the key is removed and not one button works. I'm at a total loss.

Someone has fitted a parrot unit which is the only thing I can think would affect it but I'm not electrician so any help would be appreciated.

Regards, Mark.