Consumer Redressal

Dear Sir, I had booked a flat in Panchsheel Wellington in year 2008 area crossing republic Ghaziabad (UP). Builder has committed us to handover the possession within 3 years from date of flat booking. Now they have been delayed more than a year and as per terms agreed in writing if they failed to deliver the flat within agreed time frame, then they will pay us penalty of 5 sq feet/month. But now builder is not ready to pay the same & saying that this delay was due to force measured, which is not correct. However they are asking late payment charges with 24% compound interest from us after four years. It is for 7 days delay in payment made to them during flat booking which was actually delayed due to loan disbursement from bank. Please advice on this matter, how should we take us this matter? Regards Nitin Sharma