Headphones level and cue mix knobs are not working

Hello,

I just bought my new DJ controller and I was so hyped about it until i was faced to this issue. It is not my first controller and i have never faced such a problem before. My DDJ GRV 6 headphones level knob isn't working. I have tried plug/unplug restart and reinstall softwares, i tried it on both serato dj pro abd recordbox and no response, it is not the only knob not responding, the mix knob does not work neither. I am starting to think that it is a manufacturing issue because i discovered that the effect level/depth does actually change the level of the volume on my headphones wich seem very weird.

Thanks in advance for your help.