I have lost my two factor device

If you have a backup code

You are fine. At the two factor prompt, enter a backup code instead of the six digit code. You are signed in immediately, and that code is then used up.

Once in, go to Security, disable two factor authentication and set it up again on your new device. That issues a fresh set of backup codes and retires the old set.

If the phone still works but codes are rejected

This is a clock problem nine times out of ten. Turn on automatic date and time on the phone, wait a few seconds, and try the new code. TOTP is time based, and a phone a minute out of step produces codes that look right and are not.

If you moved phones and the app is empty

Authenticator apps do not always migrate. Check whether your old phone still has the app, or whether your password manager holds the code — many do, and people forget they set that up. If not, treat it as a lost device.

If you have no device and no codes

Write to support from the email address on the account. Recovery is manual and deliberately slow, because a quick way around two factor authentication would make having it pointless. Expect to answer questions only the real owner could answer.

If a vault deadline is close, say so in your first message. Clocks do not pause for account recovery, and that changes how the request is handled.

Afterwards

Store the new backup codes somewhere that survives losing the phone: a password manager that syncs, or printed and kept with your passport. Not on the phone that holds the authenticator.