I did a refund for an iPhone X about a week or two ago & Apple sent me the refund, but today a FedEx guy came to my house asking me to ship them the empty box. I wasn't home, but my front desk guy told me that they're coming back tommorow. The thing is I already sold the iPhone so I don't have the apple box, but I still have the shipping box. So what should I do? Should I just tell them that Apple refunded me my money & I thought the investigation was over so I threw out the box? Please help, thank you!