I would suggest marking all of those emails as spam.
Marking non-spam emails as spam because you are upset about eBay's current search problems may have other effects that you like a lot less.
If your mail provider's program decides that all email from eBay is spam because you marked those messages as spam, that may cause other problems for you down the line. And undoing that later may prove difficult for you.
By all means, temporarily disable your email updates or have your eBay emails sent to a different folder or forwarded elsewhere, or bypass your inbox entirely; but do so in a way that you know you can easily undo if you want to later.
