water connection and others

We are a family of 6 members and my chachaji ( my father younger brother) and her wife is a family of 2 people till his death, now his wife left. After his death my chachi ji started defame our family in the society in every possible manner. We have a plot which my father, my chachaji and other their other siblings got from their father, at this plot my chachaji runs his coaching, as my father is a retired government employee and mutual understanding between my father and my chachaji was quite good and not so strong financially so my father always supported him financially. But after his death my chachi started to claim whole of the plot. So she started defame us in the society. In the main house where we all live, my father always support my chacha ji but now seeing chachi's behaviour, my father does not want to continue any kind of relation with her in any form of financially. So first step what we did that we seprate our water connection and provide a temporary pipline conncetion by our end for her needs as she always missused electicity and try to creat problem for us financially. What next we should do to keep her away from us so she can't harm us either financially or mentally or in any manner.