Dealing with his crazy ex!!

My boyfriend and I started dating a year ago and his ex started dating some one new right away too but now that she broke up with her new bf now she trying to get my man back with her he told her there's not a chance in hell he would ever want to be with her but she just doesn't get it she stokes my FB page writes nasty comments I blocked her but she goes on people page we have some friends in common. I don't get it doesn't she know she looks super crazy? How do I get her to stop?