Bangalore - Can landlord charge old and new tenant both for the same month?

I had a two month notice with the landlord as mentioned in rent agreement. I had to vacate the place with one month notice as the new place and most of the places in the city has one month notice. The owner and the broker charged me one month extra(for the month of august) as the notice was of 2 months and the broker promised me to return the money when new tenants joined the same month. I gave the keys and original rent agreement to them and dropped a message to the owner that broker has promised to return some amount based on new tenant arrival. New tenants arrived somewhere in the middle of August. I called the broker in the month end to return me the money, he failed to recognise me and after a second call said evey-thing is setlled. I was shocked and felt cheated. I called the owner it is not right to charge me and also the new tenant for the same period, he lost his temper and started abusing and threatening me. The owner owns 40–50 flats in that same society and is a influential person. I am a professional and do not have the expertise to verbally and physically fight those guys. I wanted to understand was it legal what the broker and owner did? (leaving their unprofessional behaviour aside)