I've got the iPhone 5S sprint model a couple of days ago from a friend. The iPhone is still packed in the original box and the accessories are still wrapped. The phone was bought December 28th so its still under the 30 day return period. Would I be able to take it to the apple store and ask the phone be replaced for a verizon model? I don't have a receipt and I'm not sure whether or not he bought directly from sprint or the apple store.