Harassment, blocking sale, property damage by Builders, goons

Prolonged Harassment, abuse, trouble by builders, building men/women, watchmen etc who are basically goons, frauds I am a single female living with old ailing father in bangalore. I purchased a flat in April/May 2018. Builder mislead work is finished and later harassed, abused and wasted time, did mental/physical torture. I gave full money and did registration in May2018. Lot of work and documents such as NOC from builder, Khata, Electricity bill name change, receipt of 6.5 lacs, payment of old property tax etc were pending from builder. Builder and his servants kind of goons would harass, insult, abuse, create scenes for prolonged time every day and disturb us. It went on for too many months. They would harass, insult, abuse in gangs to extract more money from me. I complained to police many times. They did some work and didn't give documents. In August 2018, 3 neighbor men started abusing, insulting, doing vulgar gestures. I told them to maintain decency and decorum. They abused me and my father in mob with builders and his goondas and rest building men. They removed me from building whatsapp group. In August 2018, My adjacent flat became occupied and water seepage from from next flat balcony and utility appeared on my other bedroom walls, living room and balcony area. We were already very much shocked by all these gangs and goondas and were desperate to sell this off. We would plead everyday to builder and his goondas to recetify seepage to sell this off but they would insult, harass, abuse, demean, shout, threaten us. Buyers would hesitate to buy and keep condition to repair water seepage. I would end up crying in helplessness and how goondas would misbehave with us. In Jan, 2019, builder made a goonda as association incharge. Association is not registered. That goonda and other goonda watchman of builder asked me for money. I told them to repair water seepage and amount 6000 already owed by builder to me first. They both and other goons locked my father in lift twice for 3 hours and 4 hours and insulted, abused us in mobs. They stopped letting buyers come inside building. I complained to police and police beat watchman and removed him from building. Whole building men, women, builder, other goondas went to police station and started barking on us. Building incharge goonda charged twice physically on my father and myself. I pushed my daddy back and told inspector that they are attacking us. Inspector scolded that goonda a little and told bad mob to go out of his room. Builder was still there and he agreed to pay 50 lakhs to us. After 15 days, builder changed and told he will not pay. Like above, many episodes happened - more grave than above too. Please guide on fullproof solution and end of these goonda troubles and property damage and OC, association clearance letter to sell flat and parking fraud. Its huge mental torture, shame, worry, time wastage, financial loss for us.