Engagement Break Up

Dear Sir, In June 2015, my younger brother got engaged and after engagement seeing the girls attitude we called-Off marriage as the girl was more of dominating attitude. Many a times Girls mom came to our house and had asked sorry for her daughters wrong doing. Once we called-off the marriage, the girls mom threatened us on the forecoming consequences and filed a case of dowry harassment and Cheating and demaded 12L as compensation. Harassment - That we have asked dowry etc, as we have not demanded anything from them as of now and not even took a single rupee from them. Cheating - Since we called off the marriage. We were taken to police station and were questioned, and police found not tangible evidence for the complaint. Girls mom is a social worker and had used her influence to file the case on us. Her complaint stated, the we need to pay her the expenses for the marriage arrangement. After negotiation, we agreed to pay 6L for the expenses incurred. She even refuses to show or discuss the expenses list. She just needs 6L or else she says she will file the case. We reached an agreement and refuses that her daughter name should not be anywhere on paper and her daughter will not sign the settlement letter. Police say that they knew this lady from years and she is a characterless person. Please advice us on how to proceed us further. Is there any way we can file a case of false allegations, harassment and threaten complaint on the girls family.