Refund from coaching institute of iit jee

I joined resonance punjabi bagh at 25 may, submitting admission fee of rs 30000. my classes will be start on 7 may but after admission they frequently call me and told to atten on 1 may . we are only 6 students in our batch and the other students belongs to different batch as they mixed up for an orientation class . Next day my 12th boards result released and i decided to leave the coaching due to my low grade and unsatisfactory coaching service. i asked them to refund my money but they refuse to give it back ,but later they return only 7000 rupees and said that the remaining portion of money was deducted by the orientation class which i attended before. the orientation class was just a excuse to make student attendance . they said there are some rules and regulation through which my money was deducted but when we want to know what is the rules ,they didn't tell us.