Namebase is
a registry now.
You followed a link to Namebase Pro, the exchange that traded BTC for HNS. It was custodial: it held the coins, the keys and the names on your behalf. It has been retired, and nothing here holds a key for anybody any more.
Still holding BTC or HNS?
Both are still yours and still withdrawable. Create a wallet first so you have an address of your own, then use the withdrawal tool to send your BTC and HNS out and transfer any names to it. There is no old recovery phrase to import, because the previous service held those keys for you.
Namebase no longer runs an exchange, and there is no trading here to move you on to. HNS still trades, on venues we neither run nor endorse: finding one is yours to do, and so is the risk of using it. What we run now is a registry, and a wallet that holds your keys instead of holding them for you.
Handshake auctions still run, on chain, every day. Bidding in one now means holding your own keys and running your own node, which is what the wallet is for. Your names stay yours whether or not this site exists.