Unfortunately, while you are a minor your parents can indeed take away your stuff quite legally. That they are behaving immorally in doing so (they are) is irrelevant; the only consideration is the legal situation, and the law gives them that right.
Did Steve Jobs leave his daughter any money?
Lisa Brennan-Jobs, now a 42 year old author and a Harvard graduate, had a different experience growing up with her father than her half-siblings. After his death, Steve Jobs did make sure to leave Lisa with a multi-million dollar inheritance.