Delay and non-refund of booked unit in L-ZONE Delhi

Respected Lawyers, It will be very kind of you to address my concerns here. I booked a unit in Revanta Smart homes (L-Zone (near chhawla village) of smart city plan) in year 2015. The total cost was stated 52 lac, out of which we gave 19 lac to buy. Then, due to decreased FAR, they charged another 6 lac (total approx. 6 lac). They mentioned an expected date of delivery of project in 2021. Now, its already been 2020. A lot has also happened around Land pooling policy, intra-government issues, handover to DDA etc. So now- That time, it was not under RERA. 1. The Revanta agent told that it will take 1.5 years more from today to construction to start. 2. Another 5 years for possession of the property. 3. I cant wait till then, since, i will be paying another huge amount in rented homes. 4. I asked my money back, they mentioned it will take 1 year . (which i again can not trust) 5. They are offering another property in exchange, where they will adjust our given amount of 26 Lac. But that property will cost us around 90 lac, which is very high. In this case, when I am asking money back, they say - 1. it will take a year 2. That too without any interest. 0 % interest. I request all of you to kindly tell me, what course of action will help , if you can explain With specific to L-Zone in Delhi. please.