Landlord not returning the deposit money when there is no agreement

Vacated a 3bhk flat on 10 jan 2021. Notice was given one month earlier. We stayed in the flat for 2 years 10 months and for the last 2 years there was no agreement. Even for the 1st year of stay we signed the rent agreement but the owner did not. We requested for an agreement then the owner said that he is 83 years old and cannot come from Nagpur to Pune. After emptying the flat we asked for deposit. Then he said that deposit will be given by the builder who has the power of attorney. When we asked the builder then he makes excuses and doesn’t pick up or return the calls. After searching I found an article in times of India saying that if there is no agreement made then owner has to return full deposit. Rent was increased every 11 month and we were never told that builder has the power of attorney. Agreement could have been easily made but owner said that he does not want to spend money in traveling from Nagpur to Pune. Now for everything he is asking us to reach out to the builder who is unresponsive. His associate called and gave 4 different figures for the work to be done. (25000,27000,35000,39000) Later we learnt that owner wants to sell the flat and builder is looking forward to paint the whole flat from our money. As per times if India article and my limited knowledge I learnt that if there is no agreement then owner must return the whole deposit. Also, rent was increased every 11 months irrespective of rent agreement not being there. The flat has regular wear n tear at most but no damage at all. However, citing the intentions of the builder and owner, I would want to know what can be done legally to get my deposit back. Deposit amount: 50000/- Location : Pune