Consumer Redressal

I booked a flat in 2012 in Project Imperial Park in Central Kolkata with a promise to possession by end 2012.However till date its not handed over and there has been vague responses from KGN(Builder).I brought this through marketing agent 'Somani Realtors". Also since there was delay in getting my loan I was forced to give interest @10% to the initial owner of the flat with whom I entered into agreement along with the builder. Now I have paid 90% as per plan but no possession as of date.Builder had failed two deliver dates.Also quality of construction and materials is very poor. What are my legal options? What are my options to make them penalize for the 3+ yrs delay(no clause in initial agreement). Please help Warm regards Dr.Quazi 9831142288