I suggest that you plunk yourself at the nearest post office and raise holy hell until they honor the "insurance."
I am dealing with an accordian that was lost by the post office, and now after a year and a half, they are once again telling me that they can't find the paperwork... which I have had to resend at least 3 times.
The post office employee who "took me under his wing" to help get this resolved no longer remembers who I am or anything about it, and I guess I am just not supposed to collect on what I insured with them. Well, I won't be making that mistake again.
Last time they asked me if I wanted to insure a package, I very loudly stated that there was no point since they don't pay if they lose it.
The horror stories I know were more with FedEx than with USPS.
The most outrageous example was when a friend had sold a guitar amp, and shipped it double boxed. The inner box was the original box from the manufacturer. When it got to the person he sent it to, there was a huge hole right through the boxes and the speaker itself. Someone at FedEx had obviously driven a forklift right through the amp! FedEx actually had the gall to suggest that they were not responsible because the item had not been packaged properly! I guess you are supposed to use a titanium container? He raised a big stink and they eventually paid up, but not without a lot of foot dragging and hassles.
My friend's incident occurred with UPS, not FedEx. Also, it turns out that they were sticking to their guns not to pay, even though a forklift had been run clear through the box. The reason he finally collected was not that the item was damaged. He had the guy who bought ship it back, and it got lost in the return trip. So, he got paid not because of their negligence in destroying the amp, but because of their negligence in losing it.
Amazing.
Do you ever wonder how these people with this "insurance adjuster" mentality live with themselves after finding every imaginable way of wriggling out of their responsibilities?