First try to find out what company is behind this - if there is any.. Because if you suspect its a scam then probably they covered tracks. Site says: COINVERT LTD Trademarks belong to their respective owners. All rights reserved. Company Number: 10211392
Check this.
Then go to BitGo and write to them as they are partner it seems from logo.
Also i have no idea how you found them, theres hardly anything on google.
Use @blocktrades hes an user here and a decent exchange on the fly
I think they were listed in some article I was reading about crypto as having the lowest exchange fees, which they did, but boy, losing 1 Dash in transaction compared to being robbed of 50...no brainer now. Sorry to have taken a chance on someone other than @blocktrades.
You would loose like 0.4 DASH or so in fees.
and yes DASH right now is only going up, its not a bad sum of money gone :(