My other account's email has been shut down by Google. How do I access the account and the domains under that account?

I understand you're facing a challenging situation with your AWS account due to losing access to your Google email. Here are some steps you can take to address this issue:

1. Contact AWS Support directly. Explain your situation, including the fact that you have the account ID but no longer have access to the associated email. They have processes in place to help verify your ownership of the account and can assist with updating the email address.

2. When contacting AWS Support, be prepared to provide information that proves your ownership of the account. This may include details about the AWS services you've used, billing information, or other account-specific data. Having the account ID (851725240406) is helpful, but additional verification will likely be required.

3. Regarding your domains, explain the situation about the Gandi transfer and account suspension to AWS Support. They may be able to provide guidance or temporary measures to prevent loss of your domains while you regain account access.

4. If possible, try to recover your Google account. Google has account recovery processes that might help you regain access to your email, which could simplify the AWS account recovery process.

5. For the future, consider using a personal email address for AWS root accounts rather than a corporate or third-party email service to avoid such situations.

6. Once you regain access, set up additional security measures like multi-factor authentication (MFA) using an authenticator app or hardware token to prevent similar issues in the future.

Remember, AWS has strict security policies about changing account email addresses, especially for root accounts. The process may take some time and require several verification steps. Be patient and persistent in your communication with AWS Support.

As for merging accounts, this is generally not a standard process offered by AWS. Focus first on regaining access to your original account to manage your domains and billing issues.
Sources
Change email address | AWS re:Post
I don't have access to the email for my AWS account | AWS re:Post