NONE of that insulation is properly installed. The flanges of the paper-faced bats are supposed to be stapled to the face edge of the lumber, not on the inner faces. That's what helps form the vapor barrier. Having the studs exposed partially negates that.
All over those pictures the bats are tucked in and partially compressed. Thus reducing their insulation effect.
They finished your job with somebody else's unfaced bats remnants, instead of buying more of the proper material. Further negating the vapor barrier effect.
Same goes for the ridiculously undersized vents. Why even have them at all, or go to the trouble of new construction, just to totally hamstring it.
I'd withhold balance of payment until they unscrew it all. But if they are that unprofessional in the first place they'll likely just file a lien and never fix it.
Your best compromise solution might be to have them add a poly vapor barrier. But that might not even be wise in your location. But since you put 'Home' for that, instead of at least a region or State or mega-city, there's no way of even telling where your barrier even ought to be or if you really shouldn't have one at all.