"Mr. PayPal LoweryCBS mailed me an empty box".
or
"Mr. PayPal the item LoweryCBS mailed me was materially different than as described I would like to return it
I started selling coins on eBay about a year ago. I got scammed 3 times in my first 10 coins sold and almost gave up.
Once I started selling paper coins to buyers that I had not developed a relationship with, I have not been scammed at all.
I have had several scam attempts but they always "go away" once they realize I'm not going to deliver any other way but through the US MAIL. I report these people to PayPal & eBay before they have time to reverse the transaction themselves. Oddly, PayPal is slow to freeze the funds though. Talking to the call center in India sucks.
I also only sell to people in the in my own country (US).
This is in no way scam-proof. Scammers gonna scam. But, there is easier pickins. Predators prefer easy prey.
My eBay sales are small time. Sales of 1BTC. Some people buy two. My limit is 5 per person per 90 days (i think 90 days). I have my buyer restrictions set to the most aggressive values. I keep in contact with a few other sellers and share ban lists.
Eventually, someone else will scam me again. But with a 20-30% markup, I'll be OK.