The best thing that can happend is for yobit to be hacked and never come online again.. Would do crypto a big service, mainstream will never happend when such exchanges are around.
I guess you have withdrawn a coin where they have not upgraded their wallets, and it is sent on the old chain. I lost a great amount on that. Doubt support ever will answer.
I will never use yobit again, and will warn people about it. I will neither invest a single cent on coins that is newly is listed or gets listed there in the future.
Yobit is one of the most popular exchanges around the world, and one of the top list trusted in crypto market. Folks, it's up to you, but thanks for adding some good information about the specific website you've mention above.