Written complain isnot enough totake action against manhandling

My neighbour blocked my waste water pipe fixed with my balcony by constructing illegal room. when I watered my plants the extra water went to his room. On seeing the water in his room he got furious and came to my house in the morning. When I opened the door (my husband was not at home) without even realizing that a lady was standing in front of him he held me by my neck and dragged me outside the house and hit me. I tried to explain/discuss the fact with him but he started using filthy language. With With the intervention of neighbors he left from my floor, while leaving he warned that we will face dire consequences including life threat soon. I could not call 100 as I was in a state of shock and fear. Next day morning to add on to my problems he destroyed the seat cover of my husband's bike. I lodged a complaint to the nearby police station but no action has been taken because my neighbor's close relative is a police officer and he was present. Hence I sent the copy of my complaint to ACP, DCP, Commissioner & Delhi Commission for Women. Now the police started inquiring about the incident (after 1 1/2 months). The police officer saying the case will not be strong when it reach to the court because I didn't call the police in 100 Nos. My written complaint & photograph is not enough to take action against the culprit ? Still he is moving without any fear.