It seems you got an email from a scammer.
Are you sure we talking about Coinbase?
Another thing is why the email from Coinbase said you can only access the vault funds if you have these two keys?

The weird thing is there is no announcement from Coinbase that they are going to terminate Vault Wallet and honestly creating a Vault Wallet does not generate a private key it requires only 2FA and another email as co-signer.