I sent my old Watch 4 in the supplied pre-post box for the trade-in against my new Watch 7 three weeks ago but they now say they've not received it. I've searched everywhere on Apple to find out what to do to contact them about it but have come up against a brick wall. I should add that I live in France, not the US! So if there's anyone else out there with the same problem or knows what I should do to follow it up, I'd be very grateful.