Help with Prepaid Return Shipment Loss

I have been going around in circles with Amazon due to a prepaid return that was mis delivered. Amazon seller support is completely useless. I don't understand why Amazon even allows such incompetency. If these were my employees they'd be fired on the spot for these answers. This isn't a rant about seller support, however, though I just need to vent a little.

At this point I need the help of a mod because I don't know what else to do other than get legal help, which I really don't want to do.

The situation is we have an order valued close to $5200 that got returned from a customer, and due to a massive screw up by UPS they delivered it to the wrong address and we cannot collect the shipment. I've successfully filed a claim with UPS and they are honoring it but they are only paying out $100+shipping because Amazon did NOT declare value and of course, without a declared value, $100 is their maximum liability.

If Amazon is providing prepaid return labels for orders, they need to declare the value so in the event of a loss, we can get reimbursed. They force the labels upon sellers, don't give us a choice to do anything to the contrary.

If they choose not to declare the value, that's their prerogative, but they then need to act and reimburse us or any other seller that has this issue. This is a large amount of money, not something we can just accept as a loss when Amazon is completely at fault with their policies.

I'm hoping a mod can step in and I can get help this way outside of seller support.