I'm sorry but it's like Eejit stated,the hand is not a complete one unless two or more players show their cards to decide which one is the winner.That is a complete hand,if the other player folds before that happens you automatically win by default.That is not a complete hand,and even if you show your cards after that it doesn't matter because you won by default (the other player folded)which ended the hand before it was completed.
I really feel sorry for you and wish that you could have gotten the Royal Flush Bonus,but I think you can argue till the end of time with Carbon Poker and it won't do you any good.
I know it doesn't happen that often but next time I don't think you will raise and it will go to a showdown . THEN you will win the hand and bonus.