Ex troubles

So I dated this guy for 9 months and he decided to break up with me because he has commitment issues. After a few months of being broken up we talked again and agreed to be friends with benefits and I agreed that it was fine if he was with other women. So we have been doing that for about a month and all of a sudden he has just stopped replying to me. He checks my other social media but is refusing to talk to me, what's up?