you cant do anything. that mean you got hacked and someone steal all you had. All you can do is take proper security actions. And if are not possible, dont keep all coins on same spot. Remember we are still early adopters. Same as Gold miners on Wild west. They could find plenty of gold but they could easily be shoot and their gold stolen if not careful enough. This things will change in upcoming years. Crypto will bring a lot to internet security in the upcoming years.