Need advice on Deposit Refund from Landlord - Rent Case

This is regarding a house I rented in Mahim, Mumbai alongwith a flatmate. After our lock-in period got over, we gave a month's notice to vacate the house and did the same. However in the rent agreement it was mentioned that the tenants have to get the house painted before leaving. We agreed to do the same but the owner said he will deduct the money from deposit and will get it painted on his own and asking for a huge amount for a small house. He is not refunding the deposit back. During covid, we asked him to reduce the rent, he agreed for a month where I paid 4000 less and my flatmate paid 8000 less. This was a mutual agreement and he did not mention anywhere that he will need back this money. But now he is not giving the full deposit, not letting us get the house painted and asking for this money back. Need some advice in this case. Thanks