bittrex is a scam exchange and has stolen millions of dollars worth of cryptocurrencies from its users in the past. you can see the trust history of the bittrex announcer here https://bitcointalk.org/index.php?action=trust;u=96390
it wouldn't be surprising if you were manually selected to be scammed by their team. they are desperate for money these days too since they keep losing revenue. their total volume keeps declining every month, they have to stay alive somehow...