The story is definitely not based on any actual person or event, and I went to some effort to make sure that it was obvious fiction when I wrote the original Literotica version. I created a fantasy world where legal slavery existed and people could register as full time nudists. It's completely silly, but the idea is to explore what a world would be like if those things actually existed and how they could be used and abused. I did realise that some of it might be a bit close to home for some people, and I tried to write those scenes in a way that would avoid that or at least do them justice, but I also realised that even Disney movies often explore some very dark and real experiences for some people but that doesn't mean they don't make for good stories. Hell, the Jeffrey Dahmer story is No 1 on Netflix at the moment.
And Casey's Fall is a story. The blackmail is just one part of it. It has a classic hero's journey structure with a beginning, middle and end, exploring self-discovery, adventure and mystery. It is also a sexual fantasy, which, much like rape, kidnap, S&M and other dark fantasies and role-playing scenarios, could not and should not be experienced in reality, and would not be pleasurable if they were. Still, I made sure to include elements that distanced it from real life abuse, especially rape and underage exploitation. All characters are 18+, and I intentionally avoided any non-consensual sex involving other people. I also ensured that the protagonist got pleasure from her experiences, as horrific as much of it would be in real life, and I wrote it from her POV, putting myself in her shoes as a titillating fantasy that I could not and would not want to experience in real life. To break the darkness up a little, I also included lifeline characters like Greg and Amelia, and a comeuppance for the blackmailer in due course.
I'm saddened that you were triggered by this story, but you're obviously not familiar with the genre and you haven't read the whole story yet to see how it turns out. I am completely appalled that my story, or the Game version that Sakrilas and I are creating, could be associated with Amanda Todd in any way. Words cannot describe the rage I feel, not just towards her blackmailer, but to everyone involved in her bullying.