Problems with this guy im kinda dating (his xgirlfriend)?

Im kinda dating this guy its more of talking but it fells like we are dating in a way and he says the same thing and he says hes done with her and riped up the pics of them and told her he moved on i was there for both and now she keeps talking to him and she knows that they are not to be talking because she causes to much problems at works just simple they both said there not aloud to be together. shell try to talk to him and hell ignore her but she keeps talking even when he walks away. I had to turn her in because she got into my stuff at work and over stepping here boundaries and she wont stop so i turned her in and things calmed down but now she keeps giving me dirty looks. any ideas how to get her to stop coming between us. the guy im talking to said hes gonna turn her in for talking to him and bugging him at work. what do you guys think i should do about her? thing is she just gets in our life and trys to get me in trouble thanks