IMHO - I say let the fakes stay. 'Once Bitten, Twice Shy' and 'A fool and their money are soon parted' are two phrases that come to mind.
Sadly, you will end up in an early grave trying to take down all the
ebay listings for fake coins. Then there's Scumtree, Facebook marketplace, Craigslist etc. If a person loses 30-40 bucks on a fake it's a cheap lesson on being cautious when purchasing coins online. If a person is prepared to spend 100s or 1000s of dollars without doing due diligence on the purchase then what do they expect.
Besides, Paypal should cover their loss. If they are stupid enough to pay via Bitcoin, bank transfer, Western Union or the like then what more can be said.