Wife threatening

I got married in 2014 and my wife left me after 3 months. I tried several times to bring her back but she refuse to stay with my mother and I have set separate family after 1.5 years of separation .I have taken home loan and buy a house and stay separately form my mother. my wife stayed around 3 Months and keep fighting with me for every silly reason whenever I gave money to mother for her medicine or maintenance. I tried several times to reach her on phone but she put my number in rejected mode and I talk to their parents and asked them let set together to sort out the issue. even I told them my mother is my responsibility but they refuse to talk and send my wife....when I tried several time, I send a divorce notice after 1 years as she doesn't wanted to stay with me.... and they appeared for couple of times and demanded 50 lacks as compensation. Even after sending the divorce notice, whenever I got the chance to talk to her, I asked her to comeback to family but she refused all the time. Even I called her during my sister marriage lets sortout the issue and I need her badly for kanyadan. They haven't countered my divorce. After ex-parte divorced, they filed a counter to cancel my exparte and I have asked her to come back but she refuse to come back again and threatening to file a false against me if I'm not giving the demanded money. I'm having all call recording.