The fact that you are unable to withdraw your 2btc from your wallet doesn't make bittrex a scam, technical errors do happen sometimes and the best thing to do might be to open a support ticket on their support center, probably you might get assistance very quick. Besides, even if they were a scam, I just don't think that they will scam 2.2 btc, that's too little compared to the money they accumulate per year/month.