Pg security deposit issue

I live in Prustel Living pg in karol bagh, when I initially shifted the owner said u can leave whenever you want and no issue for rental agreement so my papa signed it. They made it for 11months without asking, now I am leaving Delhi completed 9 months gave 1 month notice period and they took 17k as security deposit which was to be settled as last month rent now they are forcing me to pay rent not adjusting security deposit. What should I do?