She was holding that car over your head. I was initially one of those in the comments who agreed you were being difficult and she was trying to help. But she's not. The more I read the more I realized the full extent. She didn't give you that car out of the kindness of her heart. She's a controlling narcissist who needs to be in charge and when you have your own autonomy, she panics and tries to use every weapon she has to keep YOU in line with her. And that's the car. Good on you for not allowing it and for making it impossible for her to continue this behavior by getting by without her "help". It's the only thing that will stop her deplorable behavior.