Sux to hear this. I've heard good things about them.
What do the bottom sides of the rings look like? Is there a lip that might make up the other .125" ? If not, are there any swirl marks where it might have been fly cut from .625 down to .500? I ask because the marks shown on the ring are stamped on @ the mill to show the make-up of the material. If they started with a piece of .625 and cut the top down, that would obviously not be there.
I'd be doing everything I could to talk to the owner of the company. If the lady answerig the phone was so willing to take back the messed up parts for a loss to you, I'd think he might like to know about it.