I mean that’s the risk of putting something up for auction. You put it up for sale and that was the price it sold at. May not be what you wanted, but that’s the result. If it’s an auction of course you can’t reject the winning bid. In any other auction house you can’t just say JK not for sale if an item you’re selling doesn’t sell for as high as you like. If you had opened it up for bids, then in that case you can choose if you want to accept an offer. Or you if you had a minimum price you wanted for it, you could have done a fixed price. Or you could have set a minimum open bid for a timed auction. There are a lot of other options available if you didn’t want to sell below a certain price, but you put it up for sale and that was the price you got.
What happened with @21be is extremely shady. Here’s a shit fact: no one should trust that NFT creator or you if you fail to hold up your end of a sale contract YOU created and YOU initiated. That kind of behavior delegitimizes that NFT space.