Coinexchange has long warned its users that it will close. This is a reputable exchange that closed as expected, notifying its customers many days before the event. As for your coins, the only solution in this situation is to withdraw them to your local wallet. In the future, you can start looking for the developers of the project, they may want to return to the service of this coin and it will begin to trade on any exchange in the future. So far, that's all you can do.