I have 10 BTG at YoBit for 2 years, their wallet was placed under "maintenance" and remained like that forever.
The only way to (try to) get it out is to change it to BTC (for 30% of real price).
That is pure scam.
THAT is not the scam part of Yobit, what you experiences is the result of this shitty exchange not being used by that many people. in order for their wallets to be able to let you withdraw they have to have a balance. and that balance will only come if someone deposits that coin to trade there. when nobody deposits anything (specially altcoins) they won't be able to let you withdraw. same with the 30% lower price. when nobody trades there, the spread becomes bigger.