Return of deposit

I rented a flat in Pune through a broker and all the dealings were done through the care taker of the flat. I paid 50000 as security deposit. Before vacating the flat I served the notice to the care taker as per the agreement and discussed the the refund policy. It was told me to me that cheque will be given to me on the last date after inspection. On last day they recovered 4000 for miscellaneous repairs which I paid in cash. To my surprise, my name in the cheque they issued for return of the deposit was wrong. Hence I returned it and asked them to give a new cheque. But I was shocked to know the owner is in US and can't give me cheque. I asked for NEFT. CARE taker promised me that he would speak with the owner and money would be transferred in couple of days. I had no choice to believe him as I was travelling to different city for my new job. Now it has been 15 days since then, but I have not received my money yet. Care taker told me that owner does not have online transfer facility and has asked care taker to manage himself as he would not return to India for at least a month. I have kept the keys with me as security. Please advise how many days I need to wait to serve legal notice. And is it wrong that I kept the keys with me.