All buyers can do if receiving one of these coins and they are not as described, is to follow eBay's 30 day MBG policy to receive a full refund.
If enough of these cases are opened against sellers, then eBay act with suspension from selling those items, or even ban the sellers permanently from their site.
Messages will not work to eBay no matter how well meaning and informative, but cases do.
@kayesar50