find here, try to block the person with help from this site http://help.yahoo.com/l/us/yahoo/mail/
Apparently? Either you ARE or you are NOT. Which is it? Now, as to what you can DO about unwanted email. You do not say what your email client is, so I can not be specific. So, for some generalities. Every email client I have worked with has the ability to set up a filter for incoming email. Then, there is also a way to deal with email caught by the filter, such as placing the email in a special folder or delete it or whatever. Just set up a filter to catch the emails you do not want, and set the action taken to dump them in the trash. In my case, I have set a filter to catch email with no "@" symbol in the TO: field and automatically dump them in the trash. If there is no address in the TO: field, it is trash as far as I am concerned and I do not have to deal with it. After all, if the email is not addressed to ME in the TO: or CC: fields, it is very likely spam. In your case, there may be something unique you can filter for in the FROM: or REPLY TO: fields or even in the body itself for this specific sender, a domain name or some such.