I am not sure if it is possible to find out who is doing this to you since the person is using your mail address. But you certainly have a nasty problem there! You might have to open a new mail account to get this stopped, but before you do that, I suggest to report your problems to Yahoo since somebody is misusing their service! To report stalking/harrassing get in touch with: and/or Customer support:. I sincerely hope you get this problem resolved!