I think it is more likely that this Wallet ID leads to the correct wallet and addresses, rather than the correct addresses have somehow disappeared from your current Wallet ID. You are absolutely sure there were no other email addresses you used 7 years ago which you may have used to sign up to blockchain.com? And have you checked all your spam folders to ensure their email isn't being automatically filtered?

If this is the correct wallet ID and you no longer have access to the relevant email address, then again, their support are going to be the only people who can help you.