I already set my Junk mail filter to exclusive and yet I am still receiving emails in my Inbox from senders not part of my contact list.

I have had this account for years, and never had an issue until recently. I have rechecked my contact lists and ‘safe senders’ to insure that only persons or groups I know are able to reach my inbox. However, obvious junk is still being sent there, for example I just received an email from @s9z.pqex3n.5ixy.net which is not even a valid domain…
Any suggestions would be appreciated.