If you still have the 12 recovery words from your blockchain.com wallet saved in 2018, the best step is to try restoring your wallet using the "Restore Wallet" feature on blockchain.com. This should give you access to your old wallet and its balance.

If your Bitcoin address doesn’t appear after restoring, try checking its transaction history using a service like blockchain.com/explorer to verify the origin of the address.

You can also import your 12 recovery words into other wallets that support the BIP39 standard, such as Electrum, Exodus, or BlueWallet, to see if your balance appears there.

If none of these steps work, it's best to contact blockchain.com support and provide relevant details, such as your old Bitcoin address and any proof of transactions.

Hope this helps! 😊