Sometime last year, I got introduced to a "scheme" that claimed it would pay you in BTC without much work. I didn't know much about cryptocurrency then. I wasn't exactly moved because I have a hard time believing in things that come easily and I'm usually suspicious of things I get easily. So... At some point I started buying the idea because I knew some few persons close to me that were making real money from it. You didn't have to refer. I didn't want to be left behind, so my curiosity kicked. I was told if have to get the application, put in some BTC and then buy a mining machine I got did all the processes voila, I was making money...
... At least for the first three days, I was making money.
After that week, we were told they wanted to make some upgrade to the app, so we won't be able to place withdrawal at the moment... That was when I knew I was in trouble. Just as I thought, the whole scheme "collapsed" and our money was gone. Ignorance did me bad.
This kind of fraud is called Ponzi Scheme and the service you are talking about is cloudmining. It has been proven countless times that cloudmining is a Ponzi schemere where they tend to make an early payout so that users will trust the system and invest more money to the platform. They also take advantage of affiliate system where you get reward of any user you can refer to avail their service. Then eventually when they have hit their target, they will run away with the money.
Cryptocurrency mining machines is real. You have to buy it and set it up in order to mine cryptocurrency. You can also rent hashes to some rig rental services but mostly the result is somehow mediocre. So if you are planning to mine cryptocurrency it is always better to buy your own mining rigs and learn technical stuff about mining. You can learn much from this board: Mining
Even if you are careful, cloud mining is proven to be a waste of money and never ROI. Once you buy a hash in cloudmining, you already lost a certain amount while waiting for your hashes to give you ROI which in the end is quite impossible because the cloudmining service will shutdown or run away with your money even before you get your ROI