Make sure you have reasonable expectations when buying mining contracts as they do not make you rich quick. You will most likely have to wait for sometime before you get your money back depending on many factors. It's just like the stock market as in it bears the risk. That said Minestore is one of the few reputable companies in the cloud mining game.
I've been using them for 2 months now and already made my initial investment back. Like any company, they had some growing pains with a huge increase in users due to the spike in Bitcoin's value. But I did receive my payments and I am looking to invest more Bitcoin in this website.