First, let's identify the reason why you do not have access to your account anymore.
Have you forgotten your password? Or maybe just getting error "Incorrect password" while entering a correct one? Guide: How to reset my Password?
Lost your 2FA device? Guide: How to Reset Google 2FA?
Your email address has been deleted? Or you lost access to it?
Do you think your account might have been compromised?
Contact us at firstname.lastname@example.org