Commercial activity in residential building on MPD 2021 notified commercial street.

Some people have bought flats in our residential building abutting a MPD 2021 notified commercial street and they have converted these flats into offices. They have encroached on common areas of the building as well and are the cause of nuisance to the residents of the building due to huge footfall of people in these offices. These people are influential and politically connected, all the residents are afraid of them and they just do whatever they want to do with the property without asking or telling the other residents. I wish to know, if offices can operate like this. Does Mixed Land Use allow people to convert existing residential flats into offices. Please provide relevant laws (is possible). What can I do individually as the others wouldn’t dare to mess with these people. I am scared too, but don’t have any choice. Will I be able to get some kind of security under law from these mafias. Thank you.