Threat of false dowry case before marriage

Hi, I'm Neeraj Kumar and working in government sector organization. On date 25.7.2017 I was engaged to a girl of same community. At that time, it was told us that the girl is preparing for competitive exams besides post graduation. The girl is not preparing for any competition exams and when the post graduation exam came she started crying for the completion of exam saying that she don't want to give exam and study further.The girl starts crying for peculiar issues. But in the meantime, the girl has asked me three times that "abhi bhi time h..aap soch lijiye, Aapko mujhse bhi acchi ladki mil sakti hai. Her father and mother has also threatened me and my relatives along with my parents to call off the marriage as the marriage was getting late and the date was not fxied. The girl started to complain about my parents and siblings to me on peculiar issues and she has no respect for them. In the meantime, we had met in some public places and she took photos both of us ,but no physical intimacy took place between us. Now, the girl again said me on whatsapp conversation that " abhi bhi shadi ki date fix nhi hui h..aap soch lijiye..Aapko mujhse bhi acchi ladki mil sakti h." Her father also misbehaved with my father over telephone. The atmosphere of girls family is not so good as they don't let come her father's all three married sisters to home and they often beat(physically harass) their old age parents. Seeing these things, I called off the marriage and now they are intimidating me and my family through our relatives to file a dowry case against me and my family. They are not returning the gifts,cash and clothings which were exchanged from both sides on the engagement ceremony. Kindly enlighten me about the provisions and steps to take as according to society and law. Thanks