that is why you never use "these" exchanges. i don't even know where did ViaBTC exchange came from!! they suddenly appeared out of nowhere because of bitcoin cash.

with that said i happily sold my BCC airdrop that i've got because of my bittrex balance in the early days while it was still high and now waiting to deposit more BCC and sell them at (sadly) lower price and i have always been getting my BTC out of bittrex smoothly.