Creating damage to property through unrepaired dents.

Hi, My neighbour living on the second floor of the triple storey GDA indipendent building has been causing continuous damage to my flat (first floor) through dents in different parts of the flat. I have seen wet dents in kitchen, bedroom, puja room, bathroom and balcony of my flat. The dents have grown so much to an extent that the walls adjoining the dent portion have started getting wet. Wall paint of those wet spots have started falling. I have made numerous complaints to Ghaziabad Development Authority, Police, Nigam Parshad and RWA. None of them could help me saying this civil dispute should be closed through mutual discussion. However, we tried for mutual discussion several times in 2 years but nothing worked out other than increasing the friction between both the families. Now due to utmost level of friction, they challenge to do whatever possible but they will not spend a single penny to repair the dents. I tried to sell the house and leave that place in search of peace but no buyers are interested to buy due to dents. Please suggest legal ways to tackle this situation.