You are scaring me Lauda.. Now I am in hyper tension about it..
Though it won't be easy for me to leave yobit instantly. Because of the altcoins I have there.
You somewhat should be concerned about it. Every time an exchange runs into *mysterious* issues that keep expanding, they usually ended up with a scam (see Mt. Gox, Cryptsy for examples).
I don't think yobit was a scam, it's been a year that this exchange platform being established in this industry. Even many of the critic members often said yobit is a scam site exchange still it continuously stand and many coins applied to their site. which means yobit established community here too.
That means nothing, and you don't know what you're talking about. By not allowing these people for withdrawing for a long time, for whatever reason, Yobit is effectively denying them their rightful money. Therefore, Yobit is also effectively scamming them. Additionally, not providing any response for a prolonged time is a display of high incompetence.