Arguements,derogatory remarks

My mother recently won a civil case for a property. She was given police protection to build a temporary wall around her property .The next day , she was asked by her lawyer to visit the site and confirm if the wall was still in place as the disputing group may have damaged it.My sister had accompanied her and it was found that the a few sections of the temporary wall was demolished.While at the site, the opposing g party, led by a Dalit female and a group of 3-4 rounded my mother and sister, brandishing sticks, spitting at my sister ,used abusive language and called her an amoral female. In the heat of the moment my sister called her by her caste name and said there is no use speaking to them. The Dalit lady has now registered a complaint with the circle Inspector and Sub Inspector stating that she was abused by my sister calling her by her caste name in a derogatory fashion. How can my family counter this as they were on the offensive side. My Mom had only gone to visit the site as per advice of the police and lawyer