@Sean *******
Gvoice is a great backup option regardless. It's free, accepts text, calls and VM. It also forwards texts to email and even transcribed VM to email. And it works around the world for voice calls on wifi (call quality is not the best though but for free it's great).
Only reason some institutions won't be successful with using it for 2FA is because there's so much fraud and they're tightening their security.