Just to follow up: Ergotech called to ask if I would prefer to receive an entire cross bar or just the hinge required. I chose the hinge; got it in a few business days, and now have it installed. The screws they sent didn't quite match with the ones already on the stand, but I'm not too concerned with that as I could just reuse the existing ones. So far so good and I'm glad that they resolved the problem.
nathan.grayStill waiting for my replacement. Massdrop support says they contacted ergotech but are unable to give me status. At their request I mailed the broken stand back to them.