Neighbours/Fellow Flatmates' harassment

Hi, We own a plot in hyderabad which was given to a builder for devp. Out of 10 flats in a 5 store apt,. the builder sold his 6 flats and the remaining 4 are owned by us. Since their occupancy, we have been facing serious issues one or the other almost every day. The person living in the floor above us has kept huge pots for plantation in his corridor. When he waters the plants, it has been draining down through granite, thereby damaging our inner walls. We have asked several times to remove them but he is adamant to obey our request. The original property documents are with us but other flat owners are asking them. When we are ready to give them the xerox set, they are insisting for original set of documents. They say, the documents should be made open and kept in common. Their suspicion is that we might have kept the docs as security to obtain any loan...... My question is what can we do with the psycho who lives above us in the scenario explained above? In the second aspect, Who should keep the original documents? It is they or we?