Wanted to swap ETH to KLAY - did send ETH to Kaikas, now it's stuck

Hello, I am quite new to the crypto scene, but I think I did a mistake here. I am trading NFT on Opensea and saw, that Klay is although accepted there… so I created a new Kaikas wallet and then want to swap my ETH to Klay (at least I though I could do it like this, similar to metamask). I sent ETH to my Kaikas wallet and then I saw, that it is not displayed in kaikas and I cannot swap it there. (My ETH balance is only displayed on Opensea itself) In Kaikas I can add Tokes of Klay and KETH, but not ETH. So how can I transfer it back, or at least swap it in the wallet to Klay?