Who do I write to about constant harment on Yahoo 360, when the several abuse forms are ignored?

Ive been hared by someone (once dated him 3 years ago) on my 360 page, & mutual friends 360 pages. He has wrote blogs, blasts & quotes about me & my family which have been degrading, slanderous & just plain harment. I have reported him through email & abuse forms over & over again, even have screenshots of it all since he has managed to delete his postings just in time. They are not doing anything about it. He has facticious pages of others, one of which is fraud & also slanderous showing obscene photos & so on. No one is doing anything about it. He posts comments of mutual friends pages haring me & their other friends on the list. Hes called me names, some just stupid, others obscenities. Im wondering why he still has his account. Im sent emails back asking what my complaints are of him. Im quite tired of replying the same things. He has even threatened my fiance with bodily harm twice on my page & its still there & they will not do anything! Time for legal action?