If you are holding it in an exchange then you could tell it to them ,
But if you are holding it on your own wallet like an online wallet then contact the developer but if it is on a cold storage or an offline wallet ,
Then there is nothing that you could do .
even I dare to guarantee that the exchange site will not replace all your losses, they will blame you for not securing your account properly, in cryptocurrency you are responsible for yourself, there is nothing you can do when your assets are stolen dude..