Fake Assistant Asked Me to Create a Facebook Event

I got an email from “Mark Divine assistant Jeff” asking me to participate in a Meta livestream event held on a specific date. Ahead of the event, he asked me to join a Zoom call so he could show me how to connect. He didn’t share his face, only his desktop. He walked me through event creation on my Meta/Facebook page with 40k followers. In retrospect, it doesn’t make sense. Why do I need to create an event if it’s someone else’s show? After the call, I noticed an email from Facebook saying that someone with a name I had never heard of joined my business portfolio using my own email address. I realized it was a scam and checked if I had another admin or manager, but there was no one. I changed passwords, set up two-factor authentication, and submitted a report to Meta. The next day I logged in to my page and everything seems normal, except that there is a data API tracking the event that I can’t delete. I don’t understand if I avoided a threat or not. Does someone know how it works and what they did? Why did they add themselves to my portfolio and not do anything? Why can’t I find them in the users/people? What else should I do to neutralize this threat? Thank you all for answering this question!