[Security Heavily Deducted]

Landlord- Manmeet Singh Location- F-3/33 Rohini Sector 16 I decided to move on the location for rent from 5th April Onwards, I paid the total amount on 27th March of 23600/- which included 6700 for first month rent 6700 for commission of the dealer through which i got the flat ,10000 for security and 200 for the agreement.I submitted all the documents along with the photographs of my roommates as well but I never got the rent agreement till date They've told me that the agreement is going to be of 11 months I decided to leave the flat after 1 months and 15 days It never was a good experience there ,so I informed Landlord informally 20 days prior to leaving the flat.I never knew that I have to provide a formal notice as these are the terms and conditions included in a rent agreement but I never got it so how can i know. All i had with me was just a receipt of the total payment made on 27th march signed by the dealer now when i went there to vacate the room I decided to get my security back , Landlord deducted 300 for water bill which was justified and 6700 as well stating that you decided to leave earlier than 11 months which was the term of the agreement I said I never got one He said contact the dealer I'm not responsible and he handed me just 3000.Is there any way I can get my money back or sue him on any basis?It was hard earned money of my father I never told this to my parents how can i tell I'm afraid of this situation.Help me