I bought BSTY from YOBIT and Withdraw it towards wallet "YNjNrFsUfA1He8vufKzEpKzaBgTficHDJ7" 15 days ago but nothing sent I contacted them in chat in support on twitter NO RESPONSE..
You should stop using this exchange the first time when you experienced the problem, even 0.01
BTC is not a small amount you should just forget. YoBit is a very problematic exchange, there are probably hundreds of cases like this reported on the forum, and customer support is certainly one of the worst you can find on crypto exchanges.
I check BSTY, and coinmarketcap is list only 2 exchanges for this coin, but 100% of the volume is on YoBit. In your case I would say something is wrong with YoBit wallet for BSTY, the transaction has not been sent yet from their side so you can not see it on explorer.
So the solution is on their hand ( hands of Yobit) But they don't respond to support tickets nor chat nor twitter. How I will recover my 0.0249 BTC worth sir?