In-Game player stuck looking up

Whenever I'm in-game my player looks straight up. (My cursor moves around like normal)
(Only this game)

If I move my mouse down fast enough I can get it to look straight but then the player view is forced right back upwards.
If I hit the escape button (to bring up the options menu) my player does not look up.
If I 'unpause' (leave options menu) then the player view goes straight up again.
Left or right mouse movements are normal.

What I've tried so far:
I've unequipped everything from my player, no effect.
I've changed my screen resolution, no effect.
I've reset my keyboard config to default, no effect.
I've reinstalled the game, no effect.
I've deleted my config.xml, no effect.
I've unplugged my mouse, no effect.
The lower FPS I set, the easier it is to push the player's view downwards.

https://www.youtube.com/watch?v=92HHWSgaedE

Any suggestions?

reinstall gunz?

1, does it only happen on this game.
2, delete config.xml from gunz directory
3, plug in your mouse to another usb port
4, fresh install your pc maybe

4 is just a last ditch option pretty sure someone can solve here with teamviewer

Very odd reinstall didn't seen to work

If you have a joystick or a racing wheel disconnect it, It sometimes triggers stuff like this.

It WAS the controller.
I didn't have one plugged in but I set the controller sensitivity to 0
Thanks

Mod close this as it has been solved.