If anything you have a claim in your work and you should send him a C&D since you probably do have a copyright on your app.
I can show him a great magic trick he could use to help offset this iPhone coin trick... I can make my entire shoe disappear up his ass.
I don't think Apple would do that, but I might be wrong. Logically, this guy is going about it the wrong way. He should be sending YOU the C&D order, not Apple. Apple isn't developing the application, so the C&D is going to the wrong people. You don't sue the people providing the platform to do the work, if the person doing the work is infringing on you; you sue that person.
Legally, IMHO, you're in the clear, but IANAL.
BL.