The worst thing you can do is not respond when someone reaches out to you. An ex-boyfriend of mine texted me this weekend--of course he wouldn't call, that's how it is these days. I ignored it and I don't ever plan to respond. Keep in mind this is the same person who has called me and hung up--he didn't leave a voicemail and we all know that's the equivalent of hanging up on someone. This is also the same person who felt that not talking to me for a week didn't mean we'd broken up--he thought we were still together (I'm certain if some guy can't or won't talk to you, he's got no business being a relationship with you).
I've sent cards, letters and emails to people and received no response. It hurt my feelings. While I'm not proud to be doing the exact same thing, I see no reason to open the door to any further communication with this person. Sometimes you just have to go with your gut. My gut says he's not a good guy, so it's not worth it.