Flat Possession Delay by 2 Approx. 2 Years

Hi, I had booked a flat in June 2012 in Wagholi area of Pune and in the agreement possession date committed was May 2014 but it's been almost 2 years since the actual possession date has been passed and still builder doesn't seems to be in situation to give possession in coming 2-3 months. On top of it, we have had multiple meetings with builders and every time he gives us new possession date and says that they would provide some extra benefits as the possession date is delayed but since last 6 months they are not willing to have a face 2 face meeting and when I visited the site I found out that work has been almost stopped due to some legal issues. I am seeking help to hire a lawyer (we are 4-5 friends currently and can get more filing case i.,e, approx 20-25 ppl) and go ahead with case in consumer forum against the builder, any leads to this would be highly appreciated. Also would like to know the pros and cons of going legal against the builder means tat in future can it be harmful to me as a buyer if I go ahead with legal process? Thanks, Prateek