[grannyknot]

You should get a refund but Vossen will probably try to get out of it. I suspect they either weren't cleaned properly before the recoat or the center caps are vibrating causing the powder coat to crack.
If you want to keep the wheels take them to a professional powder coater and ask him to strip and recoat with special attention to decontaminating the area around the center cap with a strong solvent.
When you get them back, have the tires installed and balanced then apply a tin layer of flexible cement to the lip if the cap and snap them in. Don't remove the caps until it's time for new tires.