There certainly was a shortage of information in that article, but that doesn't mean you have to make stuff up. No mention of whether the ladies were coerced may mean that they weren't coerced.

As to why they arrested no customers.. I can't say. Perhaps the police were just following up on advertisements online, in which case no customers would have been involved.

I do find it strange that this campaign, aimed at child prostitution, netted 10 women in their 20s and 30s but no minors.