Ebay is going to side with anyone that forces a chargeback. The scammer Erin will not get any money back unless the actual product is returned. Make sure you place marks on the products that the buyer cant find them, or record some type of single product specific number such as a serial number. Or place labels on the item, with your own internal numbers that the stickers are noticeable seen if tried to be removed. LIke those stickers that say void if removed and when they remove or attempt to remove it it shows the words on the physical product and its removed from the sticker itself, so yo uknow the product has been tampered with by the buyer.