Tell Them that its out of your hands since its usps fault with the time prove the tracking that it is at their mail center or where ever it now is legally you are covered since you can prove you have sent the item and its not your risk if it takes time
Best regards hope you get it sorted
I Would if i could im first back around christmas but Then i buy you a beer if its possible and you are near by its hard to get around up there dont Got a car when im up there