I placed bet on Novak to win ,but he took retirement, so on Cloudbet what should be the status of my bet? Void or lose?
Their rules: https://www.cloudbet.com/en/sportsbook_rules
One full set must be completed for money line wagers to stand. If less than 1 set is completed, all money line wagers will be void. The winner of the match is the participant declared the victor by the umpire of the match.
Your bet lost. Since he played 1 set, the bet is not refunded. Since he lost that set, I believe the umpire would have declared his opponent the winner (I didn't check, but it's very reasonable to assume that), and therefore Novak didn't win.
You shouldn't be betting with rules you don't understand - make sure you read them through and understand them beforehand.
I agree, from your rules stated this was the result of what has transpired. It is unfortunate but that is part of sports betting.
Since you placed your bets on this, you are bound by their rules and such rules doesn't really affect a lot of players that is why it wasn't in anybody's mind.