It's the USPS's fault.
Ever see their commercial where they show a guy dropping some brake pads in a box & closing it up using just the glue strip on the flap to seal it then handing it off to the carrier?
No padding,no filler,nothing,just drop it in & yer good to go,yesiree.
Some dimwit sees that & thinks cool, that's quick & easy, thanks for making my already simple life easier USPS!
If the seller did have insurance for anything over $50.00 then the cost of shipping would reflect that & not the flat rate $5.80 on the postage label on the box in the bag.
Plus there would be a separate insurance form stub/lable with a bar code & number affixed to the box.
That's assuming the sender took the package to the PO himself & dealt with a clerk, which the labels indicate.
Self help kiosks & online printed labels are different in my experience.
If, IF the knife is worth more than $50 the seller has some esplainin' to do.
Also does the city on the postage label match the senders city or the city the last sorting facility to handle it is located?
I had a Money Order in a Pri envelope go missing at a sorting facility up here & a well packaged knife go missing somewhere in Texas after leaving a sort facility on the way to it's final destination.
I had the knife insured & the buyer got his money back & the MO was covered by the USPS so there was no financial loss.
Oh yeah, I also had a maker here on BF send me a knife without a sheath or any type of protection on the blade, in a flat rate document envelope.(the thin cardboard type)and the blade tip was poking out of a big hole in the side of the envelope.
I was amazed no one was injured & the knife wasn't confiscated.(everyone got lucky on that one)
(The maker had his wife do the shipping that week he said & he's since been banned with last known whereabouts in MO somewhere.)
Ya just never know whats going to happen with your package once it leaves your hands so it's best to take every precaution to ensure it arrives safe & sound.
No rattling around in the box & tape,tape,tape it up.
I hope this situation works out to the positive for you KC.