Wife not coming to matrimonial home. What can be done ?

I am a Hindu Male, got married in April 2015; things were going well between us after marriage. We had a minor argument after which my wife called her relatives and left to her maternal home, she was pregnant at that time. I tried to stay in touch with her and used to visit her then. She delivered baby in April 2016 and once again matter worsened between both parties for reasons still unknown to us. We tried all ways to console her and get her back, also confronted her relatives but always remained unsuccessful. I am always trying to contact her, but her phone remains switched off. I am avoiding going to her place and tried to meet her outside, however she is refusing. 1. Need advice as to whether sending legal notice to call her back is a preferred option? 2. Else, if she is reluctant to turn back, what is the way for seeking divorce? In that case what are the chances of getting custody of child? 3. Can she plot any false dowry/harassment case..?