Third floor terrace sold of to another person

During the sale of the third floor which had terrace rights, the original owner sold the third floor separately and the terrace seperately. Also Noc was taken from the me during the registration. Now the owner of the terrace started construction and the owners of ground floor & neighbours complained against the construction. The terrace owner managed to construct the fourth floor structure with slab and everything till the court gave a stay. Now the construction is stalled and hence , due to incomplete fourth floor terrace flooring etc , my floor is having serious seepage leading to inhabitable conditions. So now both 3rd floor and 2nd floor remain un occupied and the construction on fourthfloor is on hold. How to resolve this situation. 1) Should I along with the remaining floor owners file a compliant in MCD against the fourth floor owner. Will it be possible to demolish the fourth floor, but will it risk the safety of the entire building and also the salable reputation Or 2) should all the floor owners complete the fourth floor terrace ourselves thus preventing the seepage please share what is the solution or what happened in similar case since have already lost rental income for more than 5 - 6 months because of this issue Amrit west delhi Janakpuri 9810922731/9205704502