Consumer Redressal

I had booked a flat in Mantri Royale project in bangalore in august 2010. The delivery time committed was 18 months. The agreement had provison for payment of monthly rent in case of delay. So far the progress is not satisfactory and the builder is not replying on the issue of payment of monthly rents. Also the builder ( Sunil Mantri Realty Ltd. )is not communicating any completion schedule. I have already paid 95% of the flat cost. I want my money to be returned to me with interest. I want to know the legal recourse.