Father's right to custody of sons

My wife left the house in wee hours of the morning with my two sons aged 9 & 6 with the help of her brother. She also has blocked my contact. She had prevented her children from appearing for school exams. Because i did not approve the kids going to their maternal house for her cousin's marriage. she has taken leave for a year with permission to appear for the annual exams only by stating problems exist between she and her husband the school that due to problems between her and her husband. i had filed a police complaint as wife & children were missing. The police took long time to establish her location and contact. She has sent a letter that she had left for her cousin's marraige and also due to husband physical and mental torture and has no plans to return back to the marital home.The Police interrogated me and i have appraised them the happenings from time of marraige in 2014 till now.Almost one month has passed She had not permitted my kids to talk. also similar incident happend in Jan 2024 but after 6 weeks she returned in march 2024 in the pretext of attending her grandmother 40th day death rituals. Alos she excommunicated me from my kids. now i do not know how to proceed as she had blocked my number and has been shifting to different locations where her relatives are staying. Kindly help