builder charging compound interest on delay payment @24% p.a.

sir I booked a flat on dated 28/02/2011 in Faridabad under 12 month time bound payment plan accordingly i made payment upto 10 month of stage as builder raised the demand giving me letter of due instalment but there is a clause in time bound payment plan which is given below “(It is not obligatory on the part of seller to send demand notice / reminders regarding payment of instalment allottee is liable to make the payment on or before due date as per schedule given , otherwise interest @24% P.A. will be charged on all delayed payments.)” As per builder letter he demanded 11 month installment in 23rd July 2013 but as per time bound payment plan this instalment was due in 27-10-2012. All the time builder raising demand giving me letter of due installment accordingly i made the payment in due time. Builder not complete the flat in 12 month as per time bound payment plan he applied for occupation certificate in the month of July 2013 accordingly he raised the demand 11 month installment in 23rd July 2013 but as per tome bound payment plan this instalment was due in the month of 27-10-2012.this was the provision in other down payment plan every time he demand me according to this plan. I made payment in the month of August 2013 (11 month instalment) Builder got occupation certificate in the month of June 2014 accordingly he demanded me in the month of June 2014 but as per time bound payment plan this instalment was due in the month of 27-11-2012.this was the provision in other down payment plan every time he demand me according to this plan. Now the builder demanded to me penal interest as per my due time bound payment plan but i made all the payment as he demanded. Whether builder demanded 100% payment without offer of possession of flat (offer of possession is in the month of June 2014 but 100% payment demand for penal interest calculation is 27-11-2012) Thanking you Yours faithfully Jeetendar Kumar ?