I have been answering 2 support tickets for more than two months.
They allow the purchase in btc of COX and do not allow the sale when they can not be moved to another exchange. Yobit is stealing user's coin in that way and it's not the only currency they use to cheat. BEWARE THIS IS A SCAM
Yobit has been around for years but they haven't improved in term of support. I believe this is just technical error considering their numerous users that flooding their system. There is other sides of Yobit that you should aware of before you accuse it SCAM. It's really not recommended to trade unknown cryptocurrencies there. Trading major currency like BTC, ETC, DOGE, ETH and others is much safer. I hope your issues can be resolved soon.