I paid an advance of ₹80,000 and agreed to pay ₹10,000 rent for a flat. Now, the owner and the landlord are having issues and the landlord refuses to return my advance. Should I file a police complaint and get an FIR? Or is there a faster way to get my money back? What should I do?

Filing a police complaint for a civil dispute like non-return of advance rent is unlikely to be effective. You should first send a legal notice to the landlord demanding the return of your advance. If that fails, you can file a civil suit in the appropriate court seeking recovery of the advance.