Family dispute

My brother got married to my (Mama) uncles daughter recently 2 months back After they got married whenever they are personal or alone she used to cry but in others presence she used to be day as she was crying my brother said that she loved a girl before marriage and on listening to his parents words he got married if she had loved anyone forget him and lets live happily after one month saying this once she asked my brother to come to her aunts house but my brother refused to go there keeping this in mind she started saying bad about my brothers to everyone to their parents and their family along with him started blackmailing us they will keep cheating case or dowry case on us or else show that girl loved by my brother .they are saying that they are tapping my brothers and our family members phone and doing mental harassment some 15 years back my aunt that is my uncles wife that is girls mother kept case on my uncle(mama) that is on her husband that is on girls dad itself and on entire family without any reason and for their family problems they are repeating the same thing on us.My brother believed that girl and said about his past now they are blackmailing my brother. on the day after their marriage she said to my brother that she don't like him as my bother is having a slight bald she is saying that they are recording everything we have spoken to them.but we haven't spoken any bad towards them please provide us a solution whether we can lay a case on them ar get divorced