Landlord not returning security advance, My mistake or I have a solid ground?

So I took a shared 3bhk flat on rent as a flat mate in Bangalore, The main tenet who has the master bed room with ac and all acts like the caretaker and I have till now never interacted with the landlord yet. I made a huge mistake of not creating the rent agreement before moving it the flat as I was stating in a hotel which had a fly infestation right after I checked in. I went to see the house, great house fully furnished, 2 flat mates, 1 the main guy the other the nephew of the landlord. I paid the security advance of 1 lakh in 2 instalments to the caretaker through neft (never did any cash transactions). I moved in the same day 15th August 2021, more than 1 year from now. Now the agreement was in good faith that we will do it asap after I moved in. Then comes the struggle, the caretaker would not make this an easy process, There was a ton of confusion we had an heated argument lot of back and forth. I was told to book the agreement on noBroker and pay the fees. Then I was sent some agreement file by the caretaker tenet which needed various changes, needed to be done by me like updating all of the tenets details and owners details and some other stuff. This kept on going for a few months. There was a previous agreement made for previous flatmate which was causing all of these issues. Once the previous agreement was over (on feb end) I pressured them to create the agreement, We got the agreement made but they hiked the rent by 1K, I was paying 14K the new rent was 15K, I agreed to this as well in good faith. Now on June 2022 around 10-11 months later I vacated the house due to health issues. But the landlord is denying to pay a single rupee. What should I do now? do I have any case here? or suck up and take the loss as a life lesson. Appreciate any advice. The owner lives and works outside India but has an Indian pan card so is not an NRI We also got covid and the house was quarantined which also added to the delays During my tenure I asked the caretaker 2 times that I will vacate the house, once he agreed to return the security deposit if I can find a replacement which I did but then I changed my mind. I was going through hard times as I have depression and anxiety.