This is how to remove as a Barion authentication method a mobile device that's been stolen, or one you no longer use, or have sold or lost:

1. Log in to your account at https://secure.barion.com/
2. Click the arrow next to your account avatar, then select "Security" in the drop-down menu.
3. Select an authentication method on the site that you're redirected to, and authenticate yourself as usual to go on with the deletion process.
4. Click the bin icon next to the authentication method you'd like to remove.
5. 5. Confirm that you'd like to remove the authentication method.

   The Barion app running on the associated mobile device won't be able to log you in to your Barion Wallet any longer.

You need to have at least one active authentication method, so you won't be able to delete the last remaining one in the list.

You can change your mind later: you can add the same mobile device that you've previously removed as an authenticator again.