Were you active on the scam accusation board? I am not sure if you have uses the search button of the forum. I have found a couple of issues against Mercatox exchange, look at this thread who had an issue same as you and it was ETH as well, MERCATOX POTENTIAL SCAM. Seems they eventually solved the issue and the user got his/her fund back. So you should contact them from the various official social platform. We can't do anything against them since the fund already on their hand, we may ask them via PM if they have an official account on the forum.