How do I get my ex-girlfriend to stay out of my life?

Ok I know that sounds harsh, but I'm tired of the hate messages and her always saying "I want to get back together with you." I tell her I don't feel the same and she starts yelling at me "this is through facebook and yes she lives in the same town as me) quite honestly im sick and tired of it and instead of just blocking her id like to take the mature route down this road and any help would be awesome thanks.