That's it, cause bo legitimate exchange will ask for a deposit for verification purpose, they can go for extensive KYC processing if they feel some kind of money laundering or anything that goes against their terms but just smell it as scam when they ask money to release their money and this type of scam isn't new but the scammers are coming with new domains which almost resembles the existing reputed or new exchange.
The story from beginning has ingredients of scam alert. For exchange to ask for a deposit before you withdraw your fund, that means they want to further scam you. We have to raise a doubt within us when something unusual of that nature relating to money start to happen. We have to be careful from the source that we click to register whatever we are doing because that is where the mistake start from. Regarding to exchange, I think we can be better searching through CMC to get the actual domain of an exchange.