Missing FBA Inbound Shipment (Reimbursement)

Don't know what happing in amazon Fulfillment centers all inventories going missing.

when we open case for reimbursement they simply reject even we show them all proofs.

One of our product which we sent in 2 shipments 2 boxes in each shipment to amazon 1 shipment received and we sold all units and 2nd shipment gone missing in FC now amazon saying that you sent unexpected FNSKU... and rejecting case.

FBA18M70M7CM 12 units missing Case ID 17062112701

FBA18M76X2CM 6 sold and 6 units missing 6 Units case ID 17021397771

Anyone can help?