Some info here:
https://cryptoassetrecovery.com/posts/how-to-recover-blockchain-legacy-mnemonicsIf you need to recover your Blockchain wallet, you need a few separate pieces of information:
Your Wallet ID (which includes 32 alphanumeric characters and 4 dashes. It takes the following format:
xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
Your password
Control of the email address associated with your wallet (if you have registered an email with your wallet)
Do you still have the same email address you signed up to blockchain with?
If not:
https://cryptoassetrecovery.com/posts/not-receiving-blockchain-authorization-emailsHow to Change the Email Address Associated with your Wallet
Blockchain has a process to change the email address associated with your wallet. If you can reassert control of the email address, that is generally a faster way to recover access to your wallet. But, if you have tried to regain control and failed, then this is your last option.
You’re going to need to contact Blockchain's support team and prove to them that you are the rightful owner of the wallet. They will generally ask you for the following information:
The email address currently associated with the wallet
The email address that you want them to change it to
Your Wallet ID (this will be an alphanumeric code that has this format: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
The date that you created the wallet
The two-factor authentication type (if any) associated with the wallet
The SMS number associated with the wallet (if any)