I really want to text him, but should i? please help(:?

So i dated this guy for a month and a half, we broke up, stopped talking, then we saw each other at his graduation and he hugged me and said how he misses me alot and how he messed up. well he told me to text him cus he didnt have my number. long story short he had to go outa town and when he got back we were supposed to chill. Whenever i text him i dont get a reply, but i dont think hes ignoring me because i really didnt do anything.. should i have someone else text him and see if he replys to them, and then text him? or text him and then have someone else text him to see if he replys?