Did they warn you that you were at risk of "socialized" losses in volatile market moves? If they warned you before you traded then you knew the risks and they are only doing what you knew they would do in a violent market move. If you weren't warned you were at risk of "socialized" losses then they should take responsibility.
They have it in their general terms and conditions. This can happen to everyone who is trading on these exchanges with high leverage. Play safe and trade on bitfinex and btc-e. Take lower leverage and trade with more bitcoins