The only proven 'cloud' mining company is genesis-mining. By proven I mean that they really have mining facilities in Europe. I've seen plenty of videos inside one of their mines and there even was a non bias documentary in one of their facilities. So it's definitely real. I'm not sure of the other ones (hashflare, hasing24,...). I recommend to always look for video footage of a company's facility to make sure you won't fall for  a scam.