Maintenance charges in case house purchased by someone else

My.father purchased a property first his name and second my name. My father paid maintainance till 2012. The original aggrement is with my mom. society is asking for maintainnce from 2008. The name of property is still in fathers name. My mom states its her right, she has documents, keys. My sister states its her right. Who should pay and why. The investment was done by my father. Should i pay the maintainance and if not paid by anyone what happenes.