Please we need urgent help

Dear Sir, We are muslims. My father has two brothers and two sisters. The middle brother has passed away thirteen years ago. My father is the eldest son. He left USA to serve his parents in India. Our widowed aunt with a daughter and a son lives on the ground floor with our grandparents at our shared house. My father lives on the first floor which he has constructed himself. On the pretext of looking after my aged grandparents , my aunt (second sister) has built her residence on the second floor. This aunt of mine already has well-furnished bungalow in the same city. My mother belongs to upper caste and father belongs to lower caste. This fact of lower caste was kept secret at the time of our parent’s arranged-marriage by my father’s family. My mother and her brother were married to my father and his sister respectively. Since my father has two daughters, he was subjugated and exploited from the beginning by his family. My paternal aunt (phuphi) tried her best to break my marriage by letting her daughter indulge in cyber affair with my husband. She even offered a huge amount of money to my father to leave his parental home forever. In 2006, my grandfather under the influence of his daughter (phuphi) and son-in-law (who is also our mama) executed a will in which he debarred our father and his family from using the common garden, terrace and garage. My grandmother’s brother and her son-in-law (who is also our mama) were the witness of this will. Both of them are of upper caste. We have started receiving anonymous threatening letter in our mail box. These have been submitted to our nearest police station. Ever since our father has started earning a decent salary, all his family members are harassing us and making our lives miserable. At times, they cutoff our water supply, throw out our car from our residential premise and break our cctv cameras which we have installed for our safety and security. The youngest brother of my father who is a US citizen has threatened my father over phone to take out the cctv cameras or face grave consequences. Please advise us if this biased and prejudiced will is valid under Indian jurisprudence with regard to Mohammadan law of succession? What ways we have to protect and safeguard ourselves from such suppression and torture?