Advice for inter caste love marriage problem

I am santhosh from andhra pradesh. I loved Madhavi belongs to another district. We are in love from when we are studying B.Tech(2008-12) in same college and same group. We decided that we will marry with parents permission only. So when i got the job, i asked my parents & her father to agree our marriage. They also agreed. Her fayher came to my home dates also fixed. But the problem started now in her home because her mother is not agreed for this also blackmailing her that if she will marry me & didnt other get marriage belongs her marriage she will die. Thats the reason my marriage is cancelled. After i went to her home with my family to convince her mother. But her relatives not listening us. Cancelled the marriage. Her brother is belongs to police dept. I told to my family that i will go again to convince them but my parents are afraid they will do any thing to me because they are village people. After that i have no contact with her. I dont know how she is now also. I dont want to lose her. Please advice me as soon as possible. We are belongs to different castes in hindu religion. The advice send to my email id