I'm so sorry that happened to you. Yobit is notorious for being a scammy exchange. I really don't know why people still trade on it and I hope more people like you will share their experiences so the community is aware of what Yobit is doing (or in your case, NOT doing).
Thank you also for the reminder to set up 2FA. It's so easy to do but is incredibly important.
I guess people believe in big exchanges. Sounds logical that you don't have to check one of the biggest exchanges. If a lot of people use that exchange, there should be no problem. Unfortunately, that is not always true, but too many people doesn't know that.
People use Yobit not because of the large volumes and because there is Investbox with all sorts of strange coins (made by the exchange: LIZA, YOTRA, etc.).