We recommend all clients in by the time of 2FA activation to always save the barcode used, so if anything happens the client is able to reset the same.

We can't retrieve 2FA codes; however, the user can ask for 2FA deactivation so he/her is able to access the account and activate again if they wish to do so.

Please more questions, please check the Google 2FA support link or the support for any other app you have been using to try retrieve the code for activation on a new device.