I despise litigation but perhaps that's the best solution to solving this - especially when it also involves lies and blackmail. Maybe people will think twice if there are very real consequences involved.
For everything else, I just use throwaways.
And I hate that my name is traceable back to my time in 2007 because it was so cool to use the same unique name everywhere. Nowadays Facebook, Instagram, LINE all are "serious" accounts but all have different IDs and lack my last name.