Sibling rivalry

I am the only son of my mother & I have an elder sister who is 2years older to me. Since our father passed away both me & my sister have contributed equally in handling the financial expenditure of the house. My mother does not keep well & recently she was admitted in the hospital for treatment. My sister and I were not in good terms as we both lost our jobs & there was tension between us and we have got into arguments wherein she has rushed towards me and slapped me and bruised my hands and arms and I have pushed her and stopped her. During my mothers treatment, my sister left her alone in the hospital and went to her boyfriends house with all the money that she was given to pay the bills and hospital passes and did not receive any calls and after calling and waiting on her I had no other choice than to go to her boyfriends house to bring her back. Her boyfriend got involved and there was exchange of abusive words & baseless threats between me and him where he threatened to hit me and picked up a stone and called some local boys, so I clutched onto my helmet in self defense but did not act. My sister said she does not want to come back & has not come back to the house or seen our mother ever since. Recently she sent me a notice from a lawyer of how I am calling and harassing her through calls and texts msgs and I should not bother her which is not true, I have sent her msgs only during the time my mother needed to get discharged and since she had all the money and refused to receive any calls, it is obvious to loose temper at that moment. I am very agitated and I do not know how to proceed to take any action against this & bring her back home. Please help me out with a legal solution.