Power of attorney accountability.

My sister had power of attorney of mom and for years refused to let me see her until stroke and on death bed. She has cleaned out mom's house of everything including my own art work I am an artist, furniture and clothing. My mom before sister took over power of attorney wrote a note signed saying I can have my stuff .my sister said everything was for her family even though I am also on deed of house. Do I have any recourse can she be accountable for her a tions.