Lift Sabotage And Nuisance By Co-Owner Due To Private Seepage Dispute

I am living in a builder floor ( top floor ) and in my building the upper group floor owner and 1 st floor owner has a conflict of seepage for past 2 years due to this upper group floor owner throws garbage and dirt regularly in lift and stops the lift from the lift main electricity box placed in the parking. However I dont have any cctv proof of this. These things are hampering my daily life. What should be done to stop this permanently.