If your wallet on the Cardano blockchain has been hacked, you should take the following steps:
1. Secure your remaining funds: If you have other funds in the wallet that have not been compromised, you should move them to a new wallet with a new set of secure credentials.
2. Change any passwords that you think may have been compromised.
3. Consider using a hardware wallet: If you are not already using a hardware wallet, you might want to consider doing so in the future. Hardware wallets are physical devices that store your private keys and are much more secure than software wallets, which are vulnerable to hacking.
It's important to remember to always use strong and unique passwords for your wallets and to never share your private keys with anyone.