Junk folder is always empty. Why?

Greetings, I'm wondering why the junk (spam) folder @Mail.app is always empty. When I mark emails as junk, they disappear, so that function/filter seems to be working. Just wondering why there's a junk folder at all if there's never anything in it. Older versions of Mail allowed you to track messages, view spam messages in the junk mailbox, and to unmark those messages as junk, but it appears this function is no longer user-friendly. Any thoughts why this changed, or if there's a way to troubleshoot this? If Mail thinks a message is junk, does that mean that I never see it, even if I've never seen it in the inbox in the first place, and marked it as junk?

This issue has arisen in trying to troubleshoot why I'm not receiving messages from a CA state tax account; their tech wants me to check my spam folder, but it's always empty, and webmail for the account doesn't show the message either. We tried changing the email associated with the account but same result. This could be on their end, it could be a server issue, but not being able to confirm on my end one way or the other is a bit disconcerting. Absence of evidence is not evidence of absence.

Many thanks.