Did you know that people who set up Facebook groups are deemed to be joint data processors with Facebook, and therefore jointly responsible and liable under GDPR?
Sali, did you know that?
ETA: Sali has every right to block people on her social media, and should do so if that helps her. She does not however have the right to use personal data provided for business means, whether that be on Facebook, on her website, and so on, for anything other than the originally stated purpose. The one excpetion to that is if Sali has an obligation in law to use that data differently, which evidently she does not.