FBA Shipment Lost

I'm hopeful that someone can finally assist me with this ongoing issue. I initiated case number 14552603441 back in December 2023, and to date, there has been no resolution. My FBA shipment, consisting of a whole pallet containing approximately 738 units, was reported lost by the Amazon Fulfillment Center. Despite providing the tracking ID number, my FBA dashboard continues to display only a "shipped" status. Amazon claims they never received the shipment, yet my carrier has provided proof of delivery, including the name of the individual who signed for the shipment at the fulfillment center.

I've been tirelessly contacting seller support, repeatedly opening cases, and providing requested documentation. Recently, I even submitted invoices for this shipment upon request. However, the responses I receive from seller support are generic, stating that my documents are not accepted and that my case is resolved. But to me, this issue is far from resolved, as I've incurred losses totaling thousands of dollars with no party willing to take responsibility.