Remedies available in case Top floor owner creates problems with water

We are living in builder floor of 4 floors in Delhi where Top floor owner is having roof rights. Due to some issues with Top owner, he has locked the roof entrance door and is not allowing anybody to go to terrace for checking and cleaning water tanks. It is pertinent to note that Top floor owner is an practicing advocate . We had filed complaints to Delhi Police but they had closed such complaints stating Top floor owner does not have any objection in allowing other owners to clean water tanks. Further it is pertinent to note that sale deed of top floor states that Top floor owner will allow other owners to clean their water tanks.