iPhone trade in stolen in transit with FedEx

I bought a new iPhone 11, with a trade in for my iPhone 7. Got the Fedex return box, wiped my phone clean, disabled 'find my iPhone', and cleared the password (doesn't this all actually make it easier to steal?), and now Apple is telling me they only got the empty box back.

Well maybe the return label shouldn't be so obvious 'USED iPHONE INSIDE ALL UNLOCKED AND READY TO STEAL!'

Hope I can still get my trade in back $150 is a lot of money that I don't feel is my responsibility. The return process is obviously not secure enough.

Anyone else having this problem? Did you get your money back?

[Re-Titled by Moderator]