Amazon.in - Item missed from the order

I ordered * gold bars from Amazon. It's not mistakes from the seller but mistakes from Amazon package department failure while packing the order items. I ordered three gold bars from a seller called King bullion. Quantity is three
One is *.*gm
Second is *gm
Third is **gm
I received only *.*gm in the package of box cartoon and inside box cartoon, there is another plastic box where the item was packed from the seller and plastic box is not sealed from any tape or with something. I would like to tell you that plastic box is packed by the seller and rest cartoon box packed by Amazon which has also an invoice from Amazon on behalf of seller printed.
My order was not fully secured and doesn't have security sealed from inside the cartoon that is an open plastic box where the item was placed inside it. Now my concern is Amazon package department employee took from the plastic box and then removed ** gm gold bar and *gm gold bar and not took *.*gm gold bar.

And I also had an eyewitness of a delivery person who delivered item properly and on time early delivered to me. He is the eyewitness that I in front of him opened the box and he knew that it was missing from the three order, that is two, out of which received one only. So my loss here, Amazon says no fault from their side, then how I received missing item delivered?
Someone knew it was gold order so removed my big item and kept small item which was delivered to me finally. I m helpless so kindly help me.