Did you backup your keys on Authenticator?
If you did, you can easily download the app again & sync your authenticator.
If not, you need to contact YoBit's support.
They'll help you reset it from the backend.
PS: YoBit's support is very bad, so good luck.
No i havent backed up. I had an emergency on my mobile thus i ddnt have chance to back anything up actually.
I cant find contact link on yobit tho. Support link directs me to create a ticket and i cant again cos i cant log in
Create a new account to send them a ticket. If you don't remember your username, maybe a btc address you used with them could help them to identify you. Good luck!