Yobit is a very shady site that you should not use under any circumstances.

Their support is crap, they will ignore you until the world ends. The wallets on their site is often placed in maintenance mode without any apparent reason and that seriously affects people's ability to deposit and withdraw cryptos and often will result in financial losses.

Basically, they are a shitty exchange. But still functional, just a very high risk to use them.

However, if you are being touted a yobit giveaway which you have to send money to to receive a higher amount back, it's a scam 100%. It's not even going to be the official yobit reps, it's just scammers using this trick to take your money.