Probable Dowry Case

We belong to a middle class family in Patna , Bihar. In the month of August there was marriage proposal by a girl family. I met the girl in August and based on both the family members marriage was arranged. Our engagement was to happen in November and marriage in February To purchase jewelry for the the girl, the girls family gave 5 lakh of money in bank account. Everything was going fine. We had our engagement and then we started talking over the phone. The girl always avoided me. She never used to call me. On 10th January she literally abused me telling that i am not wort her she doesn't have any expectations from me. I have whatsapp chat of all these conversations. I immediately called her parents and my parents on video call and tried to sort out the issue. The moment the call started the girl's mother was like break the relationship. It was like they wanted to call off the relationship. On 19th January we found out that the girls in having an affair with some other guy. I somehow got the call records of thr girl. The girls calls this guy atleast 4 times daily. During the meeting when my mother asked the girl who this guy was she was like I won't tell you . After this the girls family unilaterally decided to postpone the wedding which was scheduled in February. Now they are pressurizing us to return the money or else they will put dowry case. I am still okay with marrying the girl but she is not interested at all . Please help