What the heck do I do if amazon “misplaced” three of my incoming FBA shipments?

I’ve opened case after case, contacted amazon seller support on twitter, I’ve submitted all the tracking info, the invoices for the item…nothing. It’s $10k in merchandise. They just keep on saying they’ve researched it and couldn’t locate the items. This is three separate shipments, 5 frigging boxes. 1 box from a shipment that had 3 boxes they did find, but the other two boxes there’s a discrepancy.

Where do I go from here?