They are incorrect. The moxt likely reason for squeeling on a brake job is that they failed to put permatex(that blue stuff) on the shims and back of the brake pads. It does not take any longer to do the job right, and that stuff costs pennies, literally. Take it back and watch them do it right. I would not let them have my car out of my sight if I was returning to force them to do something correctly, never know what they might do