What to say when he doesn't call?

The perfect thing to do is to NOT respond. If you want him to know it bothers you, simply say NOTHING. You do this by NOT responding to his ims. Also, I will tell you that he doesn't think of you as a priority. Because if you were important enough to him, he'd make the time. All men do this. Unless they think they really like a girl. Otherwise they are just textg, im, etc. just to p time, feed their ego, get attention, etc. He's just not that into you. I would lose contact, and let someone else get to know you, who actually wants to talk to you.