Send a ticket to ata. This thread is unneeded, and to short. Therefore it may warrant a lock. Nevertheless you can still recieve help if others decide to be helpful (and not trolls)
Do you have pay pal set up? The computer works through pay pal, phones work through the app store for purchases.
Could be he bought it on his iPhone but doesn't realize you use paypal for purchases on the comp not the app store, which seems to be the main point of this post