If you've lost your device and it's signed into your Mozilla account and using Firefox Sync, you can take action to prevent someone from accessing your personal information and passwords.
Change your password and disable Sync on a lost device
- Go to your Mozilla account settings (you may need to sign in).
- Change your Mozilla account password from a synced computer. This will prevent your lost phone from connecting to Sync and gaining access to old and new passwords for synced devices and services.
- Remove the lost device from your Mozilla account's Connected Services.
- Change the passwords for any accounts you have associated with your Mozilla account. If you don't change your passwords, it could still be possible for someone else to sign into your accounts on your lost device.