Supertech Limited — flat no delivered on stipulated time as mention on bba

Address: C-1167 LIG FLATS EAST OF LONI ROAD SHAHDARA SHAHDARA Shahdar, New Delhi, Delhi, 110093

Booking date 01.09.2015
Order no. Stc \ booking \ 2015 \3063508
Flat/ space no. (R025b251406 / flat no 1406)
Floor 14th floor
Super area 840 sqft

1) the sole purpose of booking this flat on 01st september 2015, was to cater to my need of shifting my parents to a city with better hospitals, convenience and lifestyle.
2) when i booked this property, i was assured that the possession of this flat is in december 2016 as already mention in bba.
3) we have already paid inr 90% of flat amount.
4) upon arrival to check the flat, she is told that the flat is undergoing finishing and will take 4-5 months more.

I am very disappointed. This deal is unethical. It has caused me
A) reputation loss,
B) loss of my saving to huge emi,

I have sent a final notification to cancel my booking and advise how much time will it take to refund my money.