If your phone was lost or stolen, we strongly recommend that you revoke your App Passwords and change your Google Account password. This will help prevent others from accessing your Google Account from your phone.
You have several ways you can get back into your account, depending on your circumstances.
Two-step authentication adds extra security to your Firefox account by making it harder for someone else to log in to your account. If you’ve gotten locked out of your two-step authentication login, you can use a recovery code to securely regain access to your account. Alternatively, if you have a device still signed in to your account, you can use that device to disable two-factor authentication so you can log in to your account without two-factor authentication.
Change your existing code and add a strong code.Then add your user name and code to your new phone.After reset you used before phone#fxhelp