Samiah International Builders — Following up with the company to refund my deposit of Rs. 50,000/-made in 2010. Not yet refunded

In the year 2010, I was asked by one of the Samiah Builders employees to pay Rs. 50, 000/- as advance so that I would be allotted a ready-to-move 2 Room flat @Rs.4.5 lakhs at Rudrapur. I made the payment immediately with the hope of getting the ready-to-move flat. I kept on reminding Samiah Builders for allotment of the flat. But I was not allotted any flat. Then I requested for refunding my deposit of Rs.50, 000/-. I kept on reminding for the refund numerous times over last 12 years or so both in writing and over phone. My payment/ deposit has not been refunded till date. It is more than 12 years now. I request the company to please refund my deposit along with interest @ 18% p.a.