Landlord not returning the security money

I stayed in a paying guest house from 8th October 2023 to 5th November 2023 i.e., nearly a month. I had paid the rent within a week of moving in and also paid the security money on my last day of stay i.e., 5th of November 2023. I have the receipt of my payments with me on original. (Rent paid : 8000/- and Security money paid : 5000) But, I have not signed any kind of agreement with the owner/landlord and there is no written piece of contract or agreement between me and him regarding my stay and the amount to be paid to him. While I was paying the security money on the last day, the owner/landlord said to me that he will return the security money at the end of the November month after deducting some charges from the deposit. I waited for him to return the deposit in the stipulated time given by him and he did not give back the security money back to me till now. Today, on 1st December 2023, when I called him regarding the same, he is refusing to pay the amount and saying that he will not give me the money back because he said that the tenant is required to inform him about vacating the room one month in advance. I informed him about this 2 weeks prior and told him that I'll be leaving the room in the first week of November, to which he agreed and told me that he will return the money after deducting some charges. But now he is refusing to pay me and he said that it's a rule to not refund the amount if the tenant is not informing about leaving the room, one month in advance, which he did not tell me earlier. I hereby seek for the proper legal advice on how to proceed with this. Please help me