Jesus. Can't imagine how it would feel to have lost 4000 BTC like that.
I've been seeing a lot of users on twitter reporting issues with Bittrex. Been making me feel quite wary of continuing to use them. Especially because I had a very strange, weird issue that lasted about 2-3 weeks involving enhanced verification not being enough and getting locked out of my account until they took care of it for me, finally.
Going to proceed with caution when using their service and probably only transfer and sell things in small amounts at a time.