How do you block an email address from yahoo?

I receive up to 10 items of spam a day from a SENDER called "Litsa" which alway goes into my Inbox at Yahoo! mail and is not filtered into the spam folder. I can't block this spammer as each item of spam comes with a new email address even...

the harrassing emails show a yahoo email address but replies and attempts to block come back with "This user doesn't have a yahoo.com account"..how do we stop this person from harassing us? compliants to yahoo for abuse has also not worked.

Please I want yahoo to block an email address that has been sending fraudlent mails to me. How will I do it.the email address is davidson130@yahoo.com

well the question i have is that i am sharing a email account with my family and there is a person who is emailing me and i email her but my sister hates her and she blocks her address on yahoo mail and i dont want to have a new account i just want that...

I dont want to spam the address, i want to block it so that the sender gets an undelivered email back when they email me?? I use yahoo.co.uk

How do you block somebody's email address on Yahoo?

How do you block somebody's email address on Yahoo?

i have sent a scammers email address several times to spam but they keep emailing me.......how do i block them permanently????

yahoo states it provides for me to stop emailers resending spam etc but I cannot see any provision for me to permanently block these unwanted messages from the variouse email addresses.