That's about all you can do. Keep reporting it as spam and hopefully Yahoo will start delivering it to your spam mail folder instead of your Inbox. You'll find Yahoo Spam, Gmail Spam, and spam for any e-mail provider you use unfortunately.
Stop Using Your Main Email Acount to Signup for Everything!!!! Hopefully That will Stop them!!! Make A Second Account and send them there!
1) Have a separate email account for registrations. 2) Do not post your personal email address on any web site. 3) Do not have any form mails sending your address emails unless there is a CAPTCHA to block bots. If you do those 3 simple steps...occasionally you will have to mark email as SPAM.
That's a really good idea. Have one Yahoo account just for family and friends and that's it. Then have the second account to sign up for things, to use when you make money online, etc.
If ones published, actually you can not stop that. I have been suffering for that for years and found no solution yet.
You can block the email address or the whole domain if you want if you see the spam coming through the same source. Don't ask me how though, just google it.