Volume keeps going up without any press

Like subject. I was using the Apple TV to control volume. I don’t know why it suddenly can’t be controlled and the volume is going up to the max. I use back TV remote to lower the volume. And it automatically go up to the max again and again. My ears are going to deaf. Keep trying and turn off the appleTV but the problem still. At the end I have to turn off the TV and plug off the socket. May I know what is going on? I do not expect the Apple product can be like that!