The first thing you’ll want to do is log in using a backup code. Click “Use backup method to login” in the Two-factor Authentication page, and click “Use backup code you have received.”, and then enter a backup code.
After that, go to Security to change the settings of the Two-Factor Authentication by the phone that you lost. Disable it for now. After that, we recommend changing your Nulab Account password. Two-Factor Authentication can be set up again once the device is found or a new device is set up.