Blackmail

Hi, m boy from bengal. I was married to a girl but next day after marriage she said that she can't stay with me as she didn't want to marry with. She also said that her parents forced her into marriage. Then I called her parents that night and told the situation and her mother began to scold the girl but she didn't want to listen anything. Then her mother took her home and told me that she will make her understand and take time of 2 days but they didn't come. Next day I submit GD to our PS. After 7days her father came and demanded everything they had given in marriage, rupees in half they gave for expenditure for marriage and we delivered every items and1/6th of rupees and her father gave us written declaration in demi paper in presence of 4witness, in future he did not demand anything from us and leave our home.It was arranged marriage and girl is pursuing her study as she was underage.so it was not registered. Now I married to a girl now her father is demanding that rest money and blackmailing us to go to court. What should I do now.. Please help..