Why wouldn't you ship back broken parts? If they're broken, they're broken. It's not like you can use them as is, you have nothing to gain by keeping them.
Unless, of course, you're worried that the reason they're broken has nothing to do with the parts and everything to do with how they were installed/used.
Otherwise, ship them back and let Kyle figure out why they're busted. If the parts are defective, give Kyle the opportunity to find out why so he can fix future products and let others know they may need to replace their old parts.
I actually have done business with Kyle face to face, and have never had a problem with him, or the stuff I bought from him (adjustable strut rods, torsion bar reinforcing plates, front end dolly for an A body).