Bittrex is a terrible exchange, and if not for the ease of trade and variety of coins listed here, I would never use it.
Bittrex customer service is atrocious, and they take ages to respond with equally nonsense reasons. Even on the most simple questions, you will have to wait for days and days to get a response. My account hacked a couple of days ago, and despite repeated reminders via their ticket support to release it as. I have provided the identity proof; they still haven't even acknowledged it yet.
A few days ago, I asked them why certain coin counters were always "under maintenance" for many days, and they just responded to me with another lame excuse. I've noticed that when a counter is volatile, they tend to lock it and prevent us from trading.
Do not use this exchange if you have a better choice.