OMG ! Is this for real ? No offence meant to anyone.
coming to the topic I can see only 3 sellers selling Ryzen 1600x and all of them are amazon fulfilled. If my prediction is correct the problem is on Amazon's side.
Amazon fulfilled items are stored on amazon's warehouse ( they collect it from sellers beforehand ) for faster delivery. If amazon has some sort of listing / stock mismatch issue at their end things like this can happen.
USA has laws for situation like this - if merchant sent you wrong merchandise you are not liable to send it back. But here we don't have any law like this. So a merchant can take legal steps later as they are refunding back the amount. Also amazon CC is not great either - many a times you will get different answers from them.
Someone got Rs. 46000 refund for Rs. 460 from flipkart and someone got refund twice. These things usually gets noticed once they runs audit. Later they got got intimation from respective companies.
Anyway, If it sellers mistake confirm from seller through written e-mail if you can keep the merchandise. This way you will at-least have a very good legal and legit point to argue over if some situation arises later.