I am trying to get an email address out of Spam. Followed Yahoo instructions. Does not work! How to do?

I have repeatedly followed the Yahoo tutorial to get an address out of Spam (permanently) and it has not worked. Address stays in Spam. I want the address out of Spam so it is not blocked when I get emails from that person. How can I permanently get this email address unblocked from Spam and recognized as a valid email?