Landlord nor returning security deposit

Hi, I took a single room set on rent in Gurgaon and paid one month rent as security deposit but no agreement was made in this regard as the landlord did not tell for any rent/lease agreement to be made. The building was being managed by 4-5 persons. There was a problem of power back up in that building so I thought to leave that place. As no agreement was made, the question of giving one month notice did not arise; but still I informed him in advance. At the same time, due date for payment of advance rent occurred. I requested him to adjust this rent from the security deposit but he denied and told me that he ll refund the amount of security deposit later but as of now, I have to pay the advance rent. I left that building and asked him for the payment of security; he told me that he ll transfer the amount to my bank account and gave me a signed receipt of balance amount. Now, I called him for the security deposit amount and he told me to forget the refund and not to call him again as he has left that building. What can I do now? I only have the receipt signed by him for the balance amount and call recordings and whatsapp conversation with him.