Don't play the game others are suggesting. You need a serious heart to heart and face to face talk with the guy. You obviously have different and perhaps deeper feelings for him than you think he has for you. However, neither of you apparently know how to convey what your feelings really are toward each other in this case. In the period of a week, he has gone from pretty good to almost a cad because he didn't call you. Not exactly cool, but believe it or not, especially for younger people trying to get started in a business, they can get busy. And I think neither of you have progressed to handing out your work numbers to each other right? That's not as serious a relationship as people are implying, definitely, not IMO, for you to start playing games with him. You've all already assummed he was after someone else in the period of one week and he's gotten shot down by some other woman in that time. If you liked him before, and the only problem has been this one, I think the guy is worth another shot, if you have some converstations along the lines of what you expect from each other from this point on. And both of you need to be prepared for the other not being at the same level of interest with each other right now and figure out how to proceed, if to proceed from there.
But, you may both really like each other and if you react as many have suggested in this thread, you are ready to dump him when it may not be as bad as people here have suggested.
Give the guy a second chance, but explain what you thought about him and what you expected and then ask him what he expects from you as well.