If he is ignore you, then I think he should be ignore by you when he message you. try to show him that you are happy without him. this is good for you. if your place is really in his heart then he will back.
Try to find out why he is ignoring if there is something wrong. You should ask him directly if you find it right. Without knowing the reason you can't be sure n you can't do anything
If he doesn't reply, then I suggest you to move on. He must be stubborn, or just not interested. You could be doing a lot more productive activities rather then trying to get his meek attention.
