I am part of an unregistered association of an Apartment. Builder gave possession in March. Builder has not collected any advance maintenance/corpus, he did maintenance for few initial month they he handed it over to resident in June 2015 with a third party vendor. From then we made a informal association of 10-15 members who will help vendor in collection and follow up for issues. We have asked all the occupants unoccupied/occupied to pay maintenance. Most of them has paid but there are few who hold their registration for longer period like April 2016. Now they are telling us that they will pay maintenance from registration. We are already in process to register association, can we take legal action against such residents who register very late?