How to do marriage

Hi, Im a girl of 25 years old working in an Mnc. My boyfriend is of same age working in mnc too. My parents are against my love due to different caste. His parents are supporting our love but are not willing to get us married by now(since his elder sister needs to be married first). His another elder sister says that if my father leaves me without any threat to their family she can accomadate me in her home and once the other sister gets married they would marry us. MY FATHER IS A POLICE OFFICER IN CHENNAI. INSPECTOR OF POLICE. I have waited for 2 years and now things are out of hand since my parents have arranged a marriage for me this month. Myself and my boyfriend tried doing register marriage this week. But, my father has given a petition to currently working(due to cover only some are working) 3 registrar office that if my name and the boy's name come for marriage they should not do register marriage for us and to inform him(they have marked this petition as higher profile i.e more priority). since the lawyer had a person there we came to know this and stopped information going to my dad. Currently we are not sure whether he has given this petition to all districts. My boyfriend has all my Certificates and one id proof. Since my father is a police officer we are not sure will any police station will accept our complaint(that I'm being forced for marriage). our lawyer even said that the groom my family chose even knows that am in love.. so its difficult to stop marriage by telling him. Kindly let me know if there is any other way to get me married to my boyfriend. Registrar offices are not allowing us to get married. is there any law to protect a major girl from marriage by directly going to court. also its a matter of time since they are planing to get me married this month. kindly let us know if we can directly go to commissioner office and file complaint. Even though my dad is a police officer will they take my complaint?? Please note both of us are from Tamil Nadu and both of us are Hindu.