Missing Package – Advice Needed

Hi there. I had a box of fba inventory that was never scanned by UPS from my prep center. Other boxes in the shipment were delivered to amazon but not this one. It is now missing and UPS claims since it was never scanned then they never received it, and my prep center is putting blame on UPS. I additionally opened a case with Amazon but it doesnt seem to be going anywhere. I feel stuck because no one seems to want to take responsibility. I was hoping for some advice for people who have been in similar situations as I am sure this is pretty common – how can I get reimbursed for this inventory? I have limited power with UPS since the label is created from amazon themselves and not me. Thanks!