I've tried Amazon's chat function and it's put me in an infinite loop on several occasions. I don't know why they didn't have an agent available (it was business hours). I was surprised that a company with Amazon's resources doesn't have a better handle on this, until I remembered that this is the company that doesn't let you say the reason is "wrong size" when returning clothing items. They're not stupid — they're trying to make things difficult for you.
They also do not have an option to report an item they sent as counterfeit/fake which is amusing given how prevalent it is with their mixed bins between 3rd party items and legitimate goods.
The closest related option is "not as described" or something like that.
Even if you contact support chat that is the only option available to the advisers too.
So it's actually impossible to report something as counterfeit.
I always imagine some C-level exec looking at the stats and congratulating themselves on having no counterfeit items reported. Well done Bob! We did it again.
Amazon's support can be amazing. I remember years ago, when every support call was answered by a knowledgeable and helpful employee in WA. That was amazing!
More recently, I was lied to repeatedly by agents who told me that they were going to do something, or had done something already. I had to contact support many times, and the issue was only fixed after I was able to escalate to the executive support team, who confirmed I had been lied to repeatedly, and who were able to fix the problem.