UDS conveyed but Built-up area conveyed is unauthorised--remedy

Sir, I have 1/4th UDA in the Plot. Plot area 6000 sq.ft. As per CMDA and Corporation approved plan the built-up area permissible is 9000 (1.5 times). However the builder has constructed 1st 2nd 3rd floors with 10000 FSI above the permissible area. Ground and mezzanine with 4200 Sq.Ft to one owner and Basement floor of 2800 to me for office. There entire building was complete during 2006, assessed by the corporation, Electricity Board, Municipality, CMDA etc. and all are residing from 2006 by paying property tax and water tax etc. Now the Ground Floor fellow filed a writ in the court about the basement floor as unauthorised and needs to be vacated. In fact his ground floor and mezzanine floors are also double to the permissible uds (1377 - 1.5 times = 2065) but enjoying 4200 sq.ft of course my share also. What happened is he gave less UDS and built-up are constructed more than 2.5 times. Now the writ disposed by sending the papers to local corporation to decide the matter on merits. As a basement floor owner, how can i represent and submit my request. How to get the justice.