New DDJ440 Master Volume Knob not working

Hey guys, I just got a new DDJ400 and after some setup, everything works fine, except the master volume knob. Turning it does nothing and I've also tried to mess with rebinding it - I swapped it with headphones level to see if it was the knob itself. Swapping it makes me then able to control master volume, but then I can't control the headphones level (which makes me thing that it is the knob issue itself) it's interesting that it does register when you even go to bind it (so I'm guessing physically it works?) Does anyone have any advice or experience with this? Thanks!