I know this topic is old and such, but I want to say that I am so sorry about this!

I think your mom did this out of emotion, she probably was frustrated about something (as well as her not liking cats very much) and so took it out on you and your cat. It was definitely BAD communication on her part if that was it. You and your mom need to sit down and talk, and maybe have some therapist or some person to get some help to back you up if you need to.
I'd run away with my two kitties if my mom said that to me! o.O I also would wonder what was up with her.
Again, maybe you resolved this by now, and I know this topic is old, but it involves the life of your cat and how your mom treats you, and how you feel about these choices that are being made by her, so I just felt I really needed to say something here.