You could leave negative feedback and move on with your life.

Or, if you really want them to take the frame back and you paid through PayPal using a credit card, dispute the charge through your card. That will be a lot faster than going through the Ebay/PayPal resolution.

If you get involved with Ebay resolution, they might ask you to go through the process of having UPS inspect the damage, and officially say that it's not their problem. Thing is, if you go this route, it will take months to resolve the dispute. There's also the chance that UPS might pay up--if I remember right, you get $100 coverage even without insurance, which would go a bit toward a refinish, and might not be the worst thing in the world. You could either refinish it or throw the UPS insurance money at components.