....
For the people who are reading now, that hasnt 2fa on, I recommend you to do so, as soon as possible.
and if you will lose device or reinstall app which you use for 2fa you will lose and bittrex account )
look at the reviews and feedback about Google Authenticator
how about educating yourself how to use it and maybe write down the sec code, exactly the way the app/site is fucking telling you....
OP, ill offer to solve your trex issue for a small fee as it seems you cant follow simple instructions.