I used 2FA password using Authy $ email when login Yobit and withdrawing coin. But all my coins were stolen with the Yobicodes service. I do not understand why hackers can log into my Yobit account, close all my investnets at investbox and withdraw my coins with Yobicodes. Now my account is empty, no coins yet.

Check to see if you have installed suspicious browser extensions. It's a new way of stealing now.