Refund of flat booking money from real estate company

Dear Vibhanshu, May I seek a legal advice from you? I booked a 1BHK flat with Homestead Infrastructure Development Pvt Ltd in Gurgaon in year 2014 with an amount of 2.6 lac rupees. However the construction did not happen for many years. I have applied for refund of the booking amount in December 2017 and waited till August 2018. Hence, now I have been in contact with one concerned person since September 2018 and he sounded promising initially. He reviewed my documents and promised that he will start refund in one month in installments, and I have also provided all necessary documents including a cancelled cheque for account credit. After that, Since last 3-4 months I have been sending reminders in whatsapp every week, but he is not at all responding even after seeing my messages. I have all the email communications and whatsapp messages with him. Now, I have lost hope and I want to take legal actions. Please advise me what I can do and how I should proceed. Thanking you in advance! Regards, Sanjay