Follow what blurryeyed have said, since you already have a bad first experience with Yobit and you reading a lot of negative feedback toward them I would advise you to remove your funds in Yobit Exchange immediately, you are really lucky that they have credited your Zcash. Although I don't have any personal experiences with Yobit with my years of seeing bad reports against them I know that they shouldn't be trusted with my money. Also after confirming that this issue with Yobit is already resolved you should also lock the thread now by clicking "lock topic" in the bottom of the page.