I am a student went to pune for studies. I took a well known PG in pune to stay. They told me that m

I am a student went to pune for studies. I took a well known PG in pune to stay. They told me that my security deposit will not be refunded if I check-out PG before the lock-in period. I requested for check out 15 days before the end of lock-in period. At that time they told me that 30 days notice is compulsory and now they'll charge me for extra 15 days. When I asked them for the statement they sent me the image where it is clearly written that notice charges 2300 and next month 15 days charge 3800 and refund amount 5700 (my security amount was 12000). My question is 1. when I'm not taking any services from them and i don't have any dues pending then why they deducted that charge from my deposit when they have charged for notice period. 2. Is it necessary to give 30 days notice prior check-out because I have heard this in jobs that they have to give 30 or 60 days notice before leaving. 3. If my argument is right then where should I complaint about them and how. For my refund.