Ajnara India — illegal demand from ajnara le garden

Hi, I have booked a flat in D tower, Ajnara le garden in June-2013.
I received a final demand for the my unit to pay the possession charges and they have included an extra charge named as "Pratikar ".
This "Pratikar" was never discussed at the time of booking of flat and signing the agreement.
i dont have that much money that i can bear these kind of charges now, i am already having a huge homeloan and i know how i am surviving.
I requested already to waive off the "Pratikar" charge, please consider my request. Thanks.