Given 5 lac advance for property and now dealer is refusing to give property as well as money

I gave 5lac advance (2.5 cash and 2.5 through cheque) to dealer for a property(plot) which have power of attorney in ayanagar, Delhi. The full deal is of Rs.25 lac. Now he is refusing to give property and for money he keep saying us next month next month. He's not totally denying that will not refund the money but is giving time every month. Now it's almost one year he has not returned our money neither giving plot. I had a verbal agreement with dealer that we will give him rest of the payment in installments. Dealer told us he will construct one room there for us and we can live there and start paying the installments. We had some family person known to them because of which we do not went for any legal agreements. We only have one slip of dealer in which amount is mentioned, call recordings(in which dealers agree that he has taken money and will return. Later he said will not give any amount neither property and I can do whatever I want) and one small video recording where we are giving him cash. Please let me know what all legal options are there for me and how much time the legal proceedings can take?