(URGENT) Help With Missing Stock From Inbound Shipment

I recently received a large inbound shipment, of which approximately all of the units were initially checked in.

However, 30% of the units were initially successfully checked in at the fulfilment centre, shortly after, those units were suddenly removed from the shipment. When I checked the Inventory Ledger Report, the missing stock shows as being removed under the event type "Receipts" even though it was originally received.

I had also raised a MCF order to myself for the missing ASINs when the stock was first marked as received, which was successfully received by myself.... Now its saying theres no stock for this product...

I have both the Proof of Delivery and Bill of Lading confirming that the full shipment was delivered to Amazon.

Has anyone encountered something similar where stock is removed after being received? Any suggestions on how best to escalate this or get a resolution from Seller Support?

Seller Support has not been helpful at all, telling me to wait weeks to raise any investigation & that they cannot look into this for me.

This quantity would cause a massive impact financially to our business. Requesting some help from anyone who's had a similar issue.

References for Amazon Support:

FBA Shipment ID = FBA15JWHV3C8

MCF Order = Amazon order ID: S02-4252028-9023148