I got Xtrabyes stuck in Yobit and it seems nobody can do anything about it. I am still hoping though that there can be a good solution to the problem otherwise it can mean just throwing money away for no purpose at all. I am now starting to regret dealing with this cryptocurrency as I might be holding an empty bag anytime from now (if not already).
that yobit wallet was declared dead over a year ago. you aren't getting them back. you can try contacting Dominik, but don't hold your breath