Can i lible to get compansation for delayed posession

Hi Team, I bought a flat in Sept 2016 from one of the builder in pune. It's been more than 2 years now but still I have not recived the posession.Builder sold the flat by saying Dec 17 as posession date but he did not mention the same date in aggriment instead written 36 month from the aggriment date. When Rera act came , builder added date of possession Jun 18 and revised date of possession Oct 18 in Rera site. Also, few people from the same project same building have the possession date Dec17 in there aggriment but for others it is 36 months. It means Aggriment is not same for all. We have all the proofs like on cost sheet page, on email,on audio recordings where he clearly said Dec 17 then Oct 18 for posession date. We don't have any update on the possession yet and looking into current progress , it is not possible to get even in next 6-7 months. Could you please help me here.if I file a complaint in Rera,from which date I will get the compansation? Will it from Dec17 (which builder said while purchasing )? Jun18 (possession date mentioned in Rera)or Oct 18(revised possession date mentioned in Rera)?