I remember you came to me with this problem. On the same day, I contacted the technical support manager. They told me that they knew about the incident and that a special investigation was underway. Unfortunately, I do not know the details.
But I think that you are silent about something...
Although maybe I'm wrong. Believe me, this is not a mass case. It is unlikely that due to such a trifle as 15 ETH, without good reason, the Coinsbit exchange will risk its reputation.