Of course you cannot trust to any site like that, online mining services, I mean. Many sites like this one turned out to be scams, so don't invest your hard earned money into online mining. If they are giving some mining power for free use that like you can use their referral system and that can pay out for you, but do not invest your money. Good luck!
Ok, but Im just telling my experience using their services in 8 months... and with some patience I was be able to get my money back and for now one Im having only profit.
Of course 8 months ago the crypto currencies world was different... and now the ROI is uncertain, because the bitcoin price and that they rise the price to buy hashpower.
Im using this BTC calculator:
https://www.cryptocompare.com/mining/calculator/btc?HashingPower=1&HashingUnit=TH%2Fs&PowerConsumption=0&CostPerkWh=0