I happened to have the same soap bought at a Walgreens to compare it with. It smelled much worse, an unknown chemically smell, and it was about 30 percent smaller, though it still had the characteristic Dove oval shape.
If you still have the counterfeit item and a copy of the correspondence between yourself and Amazon, it might be worth forwarding...
Edit: I realise I have responded to the wrong person. The point still stands, however.
What are they going to do?
Sue Amazon? All legal precedents indicate Amazon will win
Sue the fly-by-night Chinese company? How?
When I was a seller on Amazon I got a whole bunch of scam messages from scam buyers. I reported each one and marked the message "no response needed." The latter is important because you're judged on how quickly you respond to customer inquiries. The only thing that happened was my seller account got dinged for marking too many messages "no response needed."