I’ve been selling on FBA for 10 years, this is the first time Amazon actually stole from me

I send in hundreds of shipments per year, most get to FBA with no issues (some small adjustments, but I let those go). Today, I feel cheated. I sent in 45 items and they arrived, got checked in and sat for almost 2 months. The shipment was then closed showing zero items received. Usually this is no big deal, I submit a request for investigation, they ask for invoices, I send them, they reimburse me.

10 days after starting their investigation they finally asked for invoices, which I sent in (I am the authorized distributor for this food product). A few days later, I received notification asking me for invoices for my last 40 shipments. This seemed really weird but I submitted the maximum number of invoices (6 total, direct manufacture invoices as always). Within 2 hours the investigation was closed saying my invoices did not meet one or more of the requirements, no other explanation. I attempted to request an appeal and the same associate responded saying the case was closed and there is no recourse. Amazon just stole my products and there is nothing I can do.

Has anyone else had this happen? Any way to appeal or at least get an honest human to research?