If you placed the highest bid but your bid was returned, this happened because even though your bid was submitted to the blockchain, it was not mined in-time. See: https://learn.namebase.io/about-handshake/handshake-auction#notes-on-sniping

If you had the highest lockup and your lost the auction, this was because you did not have the highest bid. Place give this a read so you fully understand how Handshake auctions work before placing your next bid: https://learn.namebase.io/about-handshake/handshake-auction