I'm looking for help. I suspect my google account has been attacked thru some un-published vulnerability. An unknown computer is still showing up as gaining a

I'm looking for help. I suspect my google account has been attacked thru some un-published vulnerability. An unknown computer is still showing up as gaining access to my google account AFTER I have done all the typical sanitation events to my google account: changed password, disconnected all apps and services, and using 2-Step authentication (even only using the Authentication, not SMS). When my account was compromised ~10 days ago, the first event in the attack was some service/app being connected to my gmail account. I regretfully did not screen shot the event (google only shows the last 10 login-events on the account). I suspect some devious 3rd party app was installed/connected to my google account and is still by by-passing all of the 2-step authentication, and "disconnect all account" actions I have taken. UPDATE: Here is URL/info where unknown computer is showing up: https://security.google.com/settings/u/0/security/activity https://security.google.com/settings/u/0/security/activity Any ideas? How the hell does one contact google on this?