Their customer service is notorious for being near non-existent, which is why you never got a reply from them. They just don't communicate with their customers the way any financial institution should, and that's really what they are. Imagine if your online stock brokerage just ignored all your e-mails regarding problems. They'd probably have some government agency up their ass within a week.
This is what I noticed too - there are so many fake customer support in twitter and other social media who claims that they are official support group of Yobit. But actually they are not. If anyone needs support then they (Yobit) strictly mentioned that you need to contact though your user account in Yobit.