Have you received a mail from firstname.lastname@example.org after a purchase on Amazon?
Amazon is very clear that fake or faked product reviews are not permitted on their website. Still, some businesspeople continue to attempt.
They're not trying to scam you, they're trying to game the review system. If you're genuinely happy with the item, give an honest review then email them, worst that happens is you waste a couple minutes writing the review and get nothing for it.
I know a few people who use these 'schemes' as their primary income, they buy items that the middlemen ask them to, leave detailed 5* reviews, get the refund, then sell the items as open box on facebook marketplace for half the MSRP/list price. That's the immoral/scam side of it though, because these people will give a 5 star review to anything since their refund depends on it. Best way to extract the truth from Amazon reviews is to only consider what the 1, 2 and 3 star reviews say.
Many Chinese sellers buy reviews by refunding the cost of a purchase in return for a 5 star review (usually this refund occurs through PayPal). Some have offered gift cards. This may be legit, but unless you have a prearrangement with the seller for a 5 star review I wouldn't trust it.