Always keep your backup codes in the cloud or in a USB in your safe.
I lost access to my Ubisoft google auth when I flashed my phone with a custom OS.
So what I did is - go to my bank statements, list 3 to 4 transactions, call their support and tossed them all the info. Trust me, most sites and services that offers 2FA auth codes keeps activity logs.
Best bet is to contact support of the app or site you're trying to access, and have them set email as primary 2FA. Hope this helps.
Oliv_r got a reaction from Underscore in Google Authenticator transfere