Fake Case of Dowry and Domestic Violence in Mediation Centre

Hi... I am from Punjab. My brother got married in 2017 to a Chandigarh based girl. It was a love marriage and everything was perfect from last 11months. She came to her parents home for Summer vacations in the month of June ( She is working as a Teacher in a private school where they get summer vacations for 1 month). When her vacations were over and she did not come back, we visited her Parents house where she refused to come with us. Almost after one month, we received a call from the Mediation Centre that she has given application against us. In that, She has written the fake story about marriage and put allegations of Dowry & Domestic Violence. We have all the valid proofs of court marriage in which neither my parents nor her parents were present and they have not spent a single penny on marriage but they mentioned a long list of marriage expenses gold jewellery in the application. Mediation Centre has given the next date for the meeting. What should we do in this matter? Kindly Suggest.