It is really very big some of money if it is true and Cloudbet  really pays such big amounts of money it is really very good. Because very often casino do not pay big winnings and suspend the accounts.

You can make a screenshot of your deposit, withdraw and winnings history then

Since you're still a newbie and can't attach image, you can copy paste the direct link from the hosting image website.

However I don't see any negative feedback on Cloudbet which mean people didn't think it's scam, but most people are complain about the long delay for Cloudbet to verification the user KYC.