Email Blacklist

I can’t see an option in yahoo to only receive mail from contacts, and it seems stupid to me I have to enter or block addresses seeing as spammers use different addresses everytime. Surely the simple thing to do rather than block an infinite number of fake spam addresses would be to block everyone that’s not a contact. Is there any option to do this?

I want to block incoming e-mails from my ex.How do I do this?

hello,
My email address is being used to send Spam with a web link to everyone in my address book. how do I stop this?
Thanks