Is Succession certificate required if family agreement is been submitted

Hi, im from a muslim family from Mumbai and our property was taken into a rehabilitation program by a private developer in the year 2010, and my father was a mentioned share holder(1/7) in this family owned property, in the year 2015 my father passed away, and grandfather also in 2016, the entire family has submitted a Family agreement deed (Along with additional deed for my Family that is me and two sisters providing consent on the payments to be released i my name) in the developers office and this was honoured by the developer and payments for a couple of years was released, however since a few years he has not been releasing the promised amounts for alternate accommodation, because of which i reached out to respective departments in MAHADA, and now the developer has asked me for a succession certificate to make any further payment. Considering that the family settlement agreement was submitted and was honoured first 2 years is the succession certificate still required (there is no dispute in my family or my fathers family regarding the submitted Agreement)? And if this is required isnt the onus of helping for all required documents on the redeveloper since this is rehabilitation program