Hmm. tough one. I also doubt that a cat would win against a kangaroo. She may be crazy but dont hold it against her for being an environmentalist or considering native wildlife a priority over a domestic animal as natives are constantly making way for development. But definitely hold it against her for being rude and aggressive. And especially if she did take your cat. Good luck keeping your cats safe until your move.
I agree. I've reared native animals before and love native wildlife, its true that cats are killing machines.... its what they do. BUT it doesn't give rise to being rude, and hurting cats either.

There are things that you can do as a cat owner but not things you can do about being a rude neighbour!! I think I would complain to the RSPCA about her anyway and let them know. If they start building a case against her she may have to learn a lesson the hard way. Let others in the street who have complaints against her to do the same. Who knows, her punishment for cruelity to animals could be having to volunteer cleaning the cat kennels