Hello,
I was also robed on YObit on May-04 at 05:42 am. My 480 USD balance was used to buy BTC (0.05) and after that complete BTC balance was clean out!.
Also using 2fa + mail code authorization. I have not receive mail of successful login, no login during that period.
I work 5 years as IT security officer in my company, and knows a lot of all kind and methods for been haked, fished etc. but this is or so sophisticated attack or someone from inside of YObit is involved! No other explanation.
How ever, reading all this posts (what I had to done before I decide to trade on Yobit), there is a small chances to get even a response from support, not to talk about refund. Only think I have is to inform so many people to
STAY AWAY FROM YObit!!