Unauthorized access to the roof of my Flat

I live in top floor , DDA Flats, R Pocket, Dilshad Garden, l have roof right as maintenance of it and water tanks of flats below my flat are kept on my roof and they can check out their water tanks and matters related to water tank . For a long time many thefts had been there of my stuff's over my roof , so I put a gate and locked it on the entrance of my roof. Flats under my roof have my contact no. so that they can call me any time to check out their water tanks . My floor is 3rd i.e. top floor . Now owner of 1st floor of my adjacent building installed TATA sky Dish over the wall of my roof which I have got repaired some month before as it was leaking and my wall has got moistened at that time. All the installation was done without my permission and knowledge and also when the gate of my roof was locked, by jumping over the wall . Neighbour should have got installed it over the roof of top floor of their building but they did all that over my roof. Now their Dish got s