She is abusive and racist and narcissistic and she told me I fed her too much (twice a day). She is black hole of a human being who yells at her for coughing up hairballs when every cat does it. If I dont get her back I swear to Christ I will invent and build a Death Star and blow up this entire planet.
If she still refuses to give the cat back, get evidence (texts, writing) that she is knowingly withholding your property from you. Some kind of acknowledgment that she is your cat. In this it should show you attempted to peacefully request your property back. If she refuses, go to law enforcement and show them this documentation and ask how you can get your cat back.
This is, of course if she wants to go the hard path. If you can avoid the cops then you should, since involving them unnecessarily puts others in danger. However, it might be a lot safer if this is done lawfully since your mom might claim you are threatening her, since she seems borderline psychotic.
I hope you get your cat back! I love my pet and couldn’t be without her.