I don't know how this would work, but if there is a dispute over ownership of the phone (ie if eBay decide that the seller must refund the buyer) whether the seller then has the right to take back ownership of the item's IMEI, which would only pass to the buyer if the transaction was successful?

And what I am saying here is, if that buyer has designs on reselling an item which is described by them a damaged, then it would be worthless if it could not be used.