Is this seller a scam?

This morning I decided to buy a copy of Windows 10, from a seller called Bravo Mirete ES on Amazon. I chose them because their price ($90) was a lot better than the rest ($120-140), and the product was shipped by Amazon.
A few hours later I started to get a bit suspicious about the price, so I went back to check the item, only to find out that it's not on Amazon anymore. I can see it in my order history, but when I click on it, it sends me to a "Sorry we couldn't fetch that page". I checked on the seller, and could not find anything else on them, other than their Amazon page, which now doesn't sell anything. They have few 5 star reviews, with (very) generic messages from June, and a single bad review (from 3 days ago) which said that the Windows 10 copy arrived on time, but that the activation code didn't work because "...had been flagged as illegitimate as it had been used too many times."
At this point, I started to strongly believe that this is a scam, so I went to cancel my order, only to receive an email from Amazon saying that they cannot cancel it, even though the item has not been shipped yet.
So my question is, should I receive the item, open it, and hope that the key works, or should I refuse and return the item to sender, and then ask for a refund?