Demand notice from builder for flat purchased under subvention scheme possible

Builder offered me scheme of subvention and under that scheme builder will arrange for loan from his tie up financial institutes to take subvention loan in my name and builder to pay interest EMI till handing over possession and no payment liability on me till the flat is ready. Agreeing to that condition i had paid booking amount of 5% under the said scheme and sale agreement was registered. Thereafter, loan was sanction but couldn't disburse due to banned of the subvention scheme by the govt. authority. Now, builder had start sending demand notice for payment as per slabwise as mentioned in the sale agreement as if I am a regular buyer without referring to the scheme under which it was agreed to buy the flat. I told since the scheme failed i want refund of my booking amount and now builder taking stand that it will be forfieted as per the agreement terms. Under this circumstances can builder claim forfieture right when the condition for sale i.e. the sale under the subvention scheme cannot be done now and the booking was purely done on that representation of the scheme and its benefits. Amt. involved is around 12 lacs. Please advise to get back the booking amount paid. Thanks.