Give us a break sometimes.

You are in a no win situation.
You are very likely to hear "He tore my heads apart, wouldn't finish them and gave me them back in peices." I would say you need to return them the way they came in plus have him sign a statement to the fact the heads are junk and not rebuildable. If you start hearing crap then you have something to back up what really happened but just handing them back in peices you have nothing.