Recently I had some troubles with my phone as it was destroyed. Unfortunatelly for me I had GOOGLE AUTHENTICATOR on it and with it access to a couple of exchanges. As I did not save the recovery codes I had to recover access exchange accounts.
I will describe for each of them how was the problem solved, hopes this helps anyone with this issue.
COINBASE :
When signing into your account you have the option that you are experiancing trouble with 2FA authentication. I followed the instruction and had to take a picture of my ID with the webcam on my labtop and finally a selfie with the same cam. At first had some troubles as the picture was not clear (a mail was send right away saying the process was not succesfull) and eventually after contacting Coinbase help, which was fast to reply saying the quality of picture was probably the problem, I made another try and it worked as the quality of pictures (number of ID) was good enough. Immediatly I received a mail that identity and photo have been verified. In about 48 hours a text message arrived on my phone saying that I can login into my account with a one time code send to my phone. The login was succesfull. It took about 72 hours to gain access to my account again.
POLONIEX:
For accesing your account after losing your 2FA code and had to open an account on Poloniex Support Center. After descreibing the situation (no more google authenticator, no recovery codes) and partly filling a form with information regarding my personal data (name, last name,mail, type of problem, recent ip address used login into my Poloniex account that I got in my mail history). The form also wanted information regarding recent deposits and withdrawals. As I used several addreses I was not able to provide the information.
A couple of hours later got a message (from the helpdesk) that it appears I forgotten to provide any recent transaction and that I should complete the form with the data. After explaining that that I have no access to the account and no idea which wallet I used for transcations, the support agent replied they can reset the authenticator but to insure the safety they will send me an email with an authentification code and insisted I provide 3 recent deposits and withdrawals (type of coin, exact amount, TX id, date). I replaid with the code they send me via mail and again emphasized that I cannot retrive information about transcations, however I did give information about the exact ammount of certain coin in my account.
The support agent thanked me for proving information however insisted that I provide information regarding deposits, registration date and balances explaining everything is for the security of my account.
24 hours after the last message I tried to access my account on POLONIEX, a 6 digit code was send to my mail and the login was succesfull. However I did not receive any messages from support saying I can login to my account.
I am still trying to get access to two more exchanges and will update the situation as soon as I can if things get moving.
What I learned from this? Always make a copy of your RECOVERY CODES when you use GOOGLE AUTHENTICATOR for accesing your account to avoid future trouble.