I have POA for my mother. What can be done to stop the actions of my family?

I was my moms caretaker for 11 years in Pa, I did all for her for many years because my family members didnt want to deal with her. I am her Power of attorney and I was exhausted and asked my sister to share her with me. She couldn't handle it (1 month) and had me pick my mom up. For 11 years I took care of my mom at home, until I was advised to get aides to help me because it was taking a toll on me. My family owned home and doctors orders I was told to admit her into a nursing home and I did. To my surprise my family decided they want to sell the house and leave me homeless. I recently moved to nyc and had my mom transferred with me and my sister now showed up with a power of attorney she had created in the month she had my mom and I am being told that they have to honor hers. When the family members never bothered to see or do anything for my mom.  They are looking to take her to another state now that I have done all for my mom. What can be done to stop their actions?  All her documents signed from doctors to nursing homes are under my name. She had that POA done in 2004 mine was done 2006 and I took care of my mom all those years and still do because I am the one that buys all she needs. They are trying to give themselves credit for all the hard work I have been through taking care of my mom :-(