Society Maintenance Payment dues

We are living in a apartment which is 2 years old in Bangalore. First year, Developer/Builder collected the maintenance and maintained the society by collecting the maintenance fund from all owners including the Ex. Land lords allotted flats. The second year, Association was formed with consent from majority flat owners. On 2nd year, some of the Ex. Land Lords not paid the maintenance fund even though they occupied the flats. When association approached to collect the maintenance funds, association was threatened by Ex. Land Lords and denied paying maintenance but enjoying all facilities and amenities like other regular paying flat owners. This Association is registered under "Karnataka Societies Registration Act 1960" and having by-laws on collecting maintenance and in fact Sale deed also have a clause that, owners have to pay maintenance to elected association. Since, its end of financial year and the ex. Land Lords still not paid single rupee, In AGM of association, its unanimously agreed to take legal action to recover the amount from the defaulters. Can you please suggest on what actions can be taken in legal grounds and its possible outcomes of that action? Any suggestions to help the situation is much appreciated.