Wait, they walked off over ceiling heights? That's like the easiest thing to adjust on paper, a half inch difference in a retail space nobody even looks up at. I mean, eight weeks in and they just bail over a change order that probably takes a day to rework? That's wild to me. Honestly, you're probably better off without them if that's their breaking point. Drywall crews can be stubborn, sure, but quitting over that shows they never really cared about your timeline anyway. I'd get three bids tomorrow, not five, just to keep it moving fast. For the schedule, I'd hire a temp crew just to lock in the ceiling grid and rough framing while you sort out the finish guys. That way you're not sitting dead in the water. And be ready to pay a little extra for speed, that's just how it goes when you're mid-project. Also, make sure the new contract has a clause about change orders and walking off. That'll save you the headache next time. Sorry you're dealing with this, man.