Not sure how feasible this is, but:
have him send you the PCM back. If it's in working condition refund a percentage of his money (75%?) and keep the 25% for yourself. Then re-list the item for sale once you've established it's fully functioning.
If it is damaged/unusable, then send him back the PCM and keep the money. Nothing you can do for him since you can't take back damaged goods.
