Warning crypto exchange Hitbtc stealing users funds.

just tried to withdraw some funds from hitbtc they suddenly raised their withdrawal fees by in many cases 100000%
for instance
a stellar withdraw on hitbtc will cost now about 68 xlm compared to for instance 0.00001 xlm on poloniex
a bytecoin withdraw on hitbtc will cost now just short of 10000bcn compared to for instance 1 bcn on poloniex
from what i have seen all currencies have been affected is this not a form of extortion??
does anybody have any ideas as to what actions can be taken against them where to launch complaint etc ?