Just “returned” a product within 5 seconds. How does this affect the seller? As I am also a seller

Bought a £4.99 birthday card on prime for somebody else as they don’t have Prime (they are gifting the card to somebody else). I explained it’s an extremely plain card and over-priced for £4.99 but they would rather pay £4.99 to have it delivered next day, then travel to town to rummage through a card shop. Fair enough.

Card arrives, the person I bought it for, doesn’t like it, of course. I don’t like returning products for the sake of “I didn’t like it”, but it wasn’t my decision. Oddly I wasn’t given an option to return to my card, just my Amazon gift balance, so I did this and received a confirmation plus “We are processing your refund. You don’t need to return the item back to us!”.

I checked the seller, the seller is Amazon so I’m not bothered about taking £4.99 from Amazon. However the listing includes the “Small Business” badge. So how does FBA work when it’s a small business, probably sending their stock to FBA, but the seller on the listing is actually “Amazon”? Are Amazon BUYING the stock, rather than selling it on behalf of the seller?