Delhi Heights — Refund not initiated

Address:

Gayatrinagar , Shiv Bagh , Karwan Road, Gudimalkapur , Hyderabad, Telangana

I am a retired employee of Telangana State Government. After seeing an advertisement in local papers under captioned Delhi housing society for affordable housing at Delhi there it was mentioned that Delhi Development Authority has prepared a PPP model for the development of residential area in Delhi under MPD 2021 approved by ministry o[censored]rban Development and under this scheme Delhi Heights Multi State CGHS is going to construct affordable housing. All government employees, retired employees and others can register this project. The draw of which was on 25/06/2018. Relying upon that advertisement that this project is a PPP model and Delhi Development Authority is partner of the Project.
I registered my name by paying Rs 25000 for MIG -2BHK Flat. I feel lucky when I saw my name in the successful candidate on the date of draw i.e 25/06/2018. There after I was informed in my mail dt 26/06/2018 that my membership no is DGH03043 and an amount of Rs 362475 to be paid within 7 days of the draw for the 1 st instalment towards share of land cost. I paid the amount of Rs 362475 on 03/07/2018 by RTGS against land cost. There after I was informed in my mail dt 24/07/2018, that Rs 375, 375 to be paid as 2 nd instalment towards balance amount against share of land cost within 30 days. I paid that amount of Rs 375375 on 03/08/2018 by RTGS.
There after I have received a demand notice dt 29/05/2019 stating that I have to pay remaining share of land cost of Rs 750750 by 30/06/2019 and failure of which an interest of 18% will be levied.
On 20/06/2019 I have raised some queries and status of the project. They have replied me 25/06/2019 and stating that the project was named as Delhi Housing Society and my member ship no is DGH03043, its exact location shall be radius of 5km of their current land of Delhi Heights Multi State CGHS Ltd and the approval is in process of submission and will take 5-6 months for DDA approval.
I came to know that they failed to get approval in stipulated time and still now they have not been successful in getting approval from DDA.
Hence on 11/08/2020 I send a mail request by surrender of our membership No DGH03043 and requested to return our paid amount of Rs 750750 to meet our medical emergency. Even tough 5 months gone after surrender of our membership request and reminded several times over phone, they didn’t responding to refund our paid amount of Rs 750750.
So I solicit your kind help for recovery of our paid amount of Rs 750750 ( Rupees Seven Lakh’s Fifty Thousand Seven Hundred Fifty).