But there are lot of true cloud mining services available for us to get benefits with them.
No, there are not a lot of genuine cloud mining operations. Most 'cloud mining' sites are ponzi scams or, at best, fractional mining ponzi scams.
or invest for free in my system "about U2cloudmining site"
you can be sure never loose.You can only earn more or earn less...but never loose.
But if they go with your normal investing ... they can loose. The number invested compared to payout unless it has changed massivly would suggest a lot of people on your system still have not made back investment -
https://bitcointalk.org/index.php?topic=852857.msg13928830#msg13928830 Feel free to update numbers as it's been a while since you released that set. But I don't see profit being made still.
Offering some "free" does not make up for other ponzi type investment that loses money. Why do you continue to post this "u2 cloud"?