Sorry to your lost but in my case I have been trading on Yobit for the past 11 months and nothing unusual I can withdraw my coins and bitcoin whenever I want,the only negative thing is support is very slow security and on time payment is good in my case or opinion.
The support is slow? I wonder whether it exists at all. If you cant withdraw your money for several weeks without any statement or message from "support" its a scam in my view.
To all new users: Please stay away from yobit.net it smells scamy