Xrbia — delay in possession of flat a8-404 at near warai and on contacts or updates available

I have purchased flat in august 2016, at the time of purchase we were told that we will get the possession by march 2018, but till date we have not received possession of the same. Every time when we call, we are told that the possession will be given in 2 months time and the delay was due to rera registration which was introduced later on, the same excuse has been given every time. It is almost 3 and half months now, we have been paying pre-emi interest on loan. Now i am trying to contact the sanpada office, but unable to contact as the numbers are showing not in existence or currently out of service, when contacted the sales office they say you can post the query on mobile app and after doing so there is no response. Even posted on the xarbia app, but no response. I have paid around 3 lacs as pre-emi interest due to delay. I want my excess interest money back, please help