Hi @jailbroken. Welcome to GoDaddy Community. In a situation like this, the best thing to do is work with the email provider that is sending the messages. Based on what you've said, the domain registrant might not even know that this is happening. If that's the case, the domain may not be suspended or redirected. My suggestion would be to continue to pursue the issue with Google if that is the mail provider.
JesseW - GoDaddy | Community Manager | 24/7 support available at x.co/247support | Remember to choose a solution and give kudos.