I want to text/email my ex and don't know what to say?

Today is 7 years from the day we met. For the past two years we have basically just been friends. Just before my mother died I found out he was spending weekends with other women and it really upset me because he said he would let me know before he persued another relationship so I could break free and move on. I finally texted him 4 months later and he called me and we spoke shortly and he said he would call me back when we had more time to talk. That was over a week ago, so today I texted him and stated: "3 months since my mother died - 7 years since we met - I take it y don't want to reamin friends by your not calling me back when you said you would - how sad." He did not respond and one part of me thinks screw him, but another part wants to email him and say something for him to think about and make him think of how rudely he treated me. I know a lot of you will say just let it go, but I'm tired of him always getting his way on his terms and the last word. I need something clever to hurt like he hurt me.