What would you do?

I am getting out of copper sorting due to many different factors, increasing fees from banks, inability to order large numbers of boxes from any source, etc. But one big reason I am getting out is lost or stolen shipments. I have made good in the past in one instance, when despite five boxes being shipped on the same day a distance of only a little over 200 miles, one box with delivery confirmation managed to disappear between Fresno and Los Angeles. In another instance, the buyer received an empty box which had been razor slit. These boxes are shipped without insurance, as to add registered mail insured shipping would add probably another $35 to their cost. I would think it would be implicit between the buyer and seller that the cost to purchase would be considerably higher were the buyer (in order to absolve the seller of all "responsibility") insist on "insured" shipping. Therefore, I have informed my buyer (of probably fifty or more boxes over the last year) that both sides must assume accountability for boxes that don't reach their destination. One must assume that the shipping of copper cents is becoming a "risk trade." In this case, the tracking confirmation shows the boxes all received at the Los Angeles receiving facility, but tracking of the one box ends there with nothing new since Oct 24. How is it my responsibility to provide a replacement if the post office lost the shipment?