I ignored them and sent the spoofed emails to the spoof addresses at both eBay and Paypal, which seemed to be entirely ignored. After the required amount of time passed I reported the auction winners as non-paying, and I finally got my seller's fees "refunded" to my eBay account.
Then, a couple of weeks ago, I attempted to get eBay to actually transfer my fee credit to my bank account. eBay responded with, "We would really love to help you out with this. but due to COVID-19 we can't."
Somehow one of the fraudulent buyers has had an eBay account since 2012, and it's still active and has a 92% positive feedback rating. Their current auctions include a used gynecological examination chair. It's as if they're flaunting the fact that they can get away with whatever they're doing without being held accountable by either eBay or Paypal.
This isn’t a hypothetical concern either, having spam filter go crazy happens more often than you expect, and some of them drop emails completely rather than putting them into a spam folder (looking at you Microsoft).
Unlike PayPal we make it easy to verify our domains. https://monzomail.com
I genuinely can't distinguish official Paypal emails from phishing emails - and that's because the Paypal emails look like bad phishing emails rather than because phishing emails are so sophisticated.
EDIT: Good write up here: https://cantoriscomputing.wordpress.com/2017/03/04/paypals-e...