It is the first time I see a complaint against Bittrex exchange. They work very well normally. I don't know what to say, as you have already contacted support there, they are the only ones who can help you with your problem. Normally I use them as my second exchange as they haven't listed as many coins as Poloniex has and I am using Poloniex as my first one even with all the complaints around, for me it is working well there without problems so far.