Are all of your employees using two-factor authentication? Are you 100% that this could not have happened via a normal security breach via a number of your empl

Are all of your employees using two-factor authentication? Are you 100% that this could not have happened via a normal security breach via a number of your employees' accounts? GMail accounts get hacked regularly, often due to users using the same password for different services, or just getting keylogged somewhere. I'm very curious too see how this pans out. Good luck with the recovery!