I am apparently pretty dumb, but I could use some advice about some possibly lost Cardano.

I am obviously a crypto noob, but I would appreciate any advice. I dabble in some coins, but I'm not a big investor or anything. I stored some Cardano on a digital wallet called C-wallet and forgot about it. They went under, and I wasn't informed or didn't check their site enough, and now it's offline. I tried to send it to Kraken, but it didn't work, obviously because the wallet is offline. I was curious if anyone had any advice or knew of a way to fix the issue, if there was one. If not, sorry to bother everyone. It's not a ton, but it's enough to try to fix. Thanks.