Nani Resorts Floriculture Private Limited - Delay in Possession of my flat and hidden charges

Hi Team, I have a flat booked in year **** in ROF Aalayas Phase-* in Sector *** in Gurgaon. At the time of booking, Builder claim that they will deliver the flat by August FY** but till now we are waiting. They have sent the letter regarding notice of possession and asked for some additional payment which is also paid. We are chasing them from past * year for possession but nobody is replying. Over and above they sent some random mail asking for some hidden charges like IFUD charges, operational charges etc. which is also paid. But still possession is not given. So I am paying rent as well as EMI which is causing double burden to me. Please help in this regard.