After being launched for almost 2 years now, Google Fi had slowly made its space in the US cellular market.
Although it’s a smooth service and switches to the best carrier available for your device time to time along with WiFi when no network is available. we have noticed that sometimes it fails to switch when the network range is not so strong for Tmobile or Sprint.
After using it for a while we were able to crack down below dialer codes. for manually repairing the fi services or switching to the best available network for your place.