Is Serangoon Broadway Studio considered a monopoly if it is the only place where you can rent/buy your graduation gowns from? If so why isn't the CCCS doing something about it?

Even if Serangoon Broadway Studio is considered a monopoly, as long as they do not abuse their dominance (such as preventing their competitors from entering the business), there is nothing against the law.

Being a monopoly isn't wrong (just like Grab now), but the way you do business because you are a monopoly will be under more scrutiny and like what Kaykay mentioned, whether you abuse this dominance.

You faced some problems with SBS? I've no issues with them and it's even better that they are a monopoly, saves me the headache to have to compare which ones offer the better rates, service etc. What's more, graduation gowns/photography is probably a one off affair, not big enough to warrant a headache unlike other stuff like savings accounts, mobile plans etc.