Security deposit disputes with house owner

I have been residing in a rental house for 8 months (from January to August). I pay ₹10,500 per month as rent and paid an advance deposit of ₹50,000 for a portion of the house. On a safer note, I have all the proofs of payment made to him, both for the monthly rent and the advance deposit. Three months ago, I informed my landlord about my plan to vacate. At that time, he stated that there is a 3-month notice period and questioned how I could leave so quickly. He demanded that I continue paying rent until I vacate, and stated he would only return half of my advance deposit at the time of vacating, with the remaining half paid a week later after deducting painting and other charges. When I requested a copy of the rental agreement, he refused, spoke harshly, told me to do whatever I want, and claimed he would not give me the agreement. He also lectured me about legal disputes, showing no consideration for my situation, even though I have only resided there for 8 months and the house was brand new when I moved in.