Same thing happened to me when I shipped a PW hydro unit to Whiz.
I cut a piece of plywood to fit the box, bolted the hydro to the plywood, put it inside the box, STUFFED the box full of packing paper, and taped it shut. There was absolutely NO wiggle room inside the box for it to shift in transit.
When it arrived at Whiz's, all of the paper was done, the box was torn open, fluid everywhere.
UPS ended up paying the claim (to whiz, since the shipment was billed to his UPS account).
The key to getting paid on insurance claims is to be PERSISTENT. Call them at least once a day, every day, until a check is mailed. If they deny your claim, appeal it, and keep appealing until a check is mailed.
I've had a couple claims through USPS, a couple through Fedex, and one or two through UPS. Every one has been paid to date.