Glad you got the adjustment!
However, was anything mentioned in writing by them on you getting the check? I would be a little skeptical if they just said "it's gonna be in the mail" suddenly after you threatened to return the car.
Please try to get it in writing if you can. I got screwed when I picked up the car on New Years eve, and they dropped the price on Jan 1st by 2K and would not honor the car return policy!