How to Handle Public Blackmail on Social Media?

I work for a mid-level below the line talent agency. Our clients are successful, but not famous in the film industry, generally. We are currently having an issue where a few of our higher-level cinematographers (for example will experience aggressive third-party social media accounts, threatening them with blackmail by posting accusations of repugnant and heinous crimes. I think they are cleverly identifying many of our clients as having enough resources to be worth blackmailing, but not quite known enough to have any real recourse beyond that of an average citizen.

Has anybody else dealt with this, and or is dealing with this? I’m trying to resolve an immediate situation, but more than that I would love to figure out a strategy for the future. My instinct is to have our clients freeze all their social media accounts after posting something explaining the situation and directing all communication to their agency toilets resolved. But I’m also not sure if that might somehow make the situation worse. Any advice would be hugely appreciated.