Payment of Delayed Possession Penalty in resale of flat

Hello, I have purchased a flat in 2014 from a seller who was the first allottee (he had purchased it in year 2012) At the time of Purchase the flat was under construction. The allottment was transferred to me by the builder and NO transfer fee was charged. My name was endorsed on the original BBA. The flat is still under construction and by the time the construction is estimated to be completed (somewhere at the end of 2015), it will be delayed by more than 1 year. The BBA says that delayed possession penalty of Rs. 10 psf will be paid to the buyer. But now the builder says that in case of resale, no such penalty is paid to the second allottee. However the BBA does not have such a clause. The catch is that the one of the affidavits that I had signed and given to the builder for transfer of flat had a clause that I will not claim for any delayed possession penalty payment. Sadly, I had ignored this while signing the papers and only got to know it recently. Can I still challenge this in courts? Can I still get the penalty amount at the time of possession? What legal remedies do i have?