I don't think it is financially worth the effort for Apple to worry about the return of a replacement phone. Not on the same value level, but last year I received extra items worth around $100 in my shipment from a pet products company and when I called to report this I was told to just keep the items or donate them to a shelter. Apparently the effort and expense of getting the items back and reselling them wasn't worth it to that company. I'm sure Apple would respond to theft but this was a mistake that doesn't affect their bottom line and getting that phone back is clearly low priority. The OP shouldn't have to spend any more time or money to get that phone back to Apple. Keeping it unopened for awhile is certainly the safe thing to do for now however since Apple didn't say just keep it or donate it.