Child custody required for son after ex parte divorce

I want to esquire about my 12 years old son's custody. I got ex parte divorce in 2018 due to domestic violence. My son was with me until one year of my separation, however due to regular threats and my plan to move out of India I had no choice but to let go off my son to his father on a condition that I will be able to spend vacations with him and will have say in his education and other decisions. However, now my ex-husband has cut all sort of my communication with him. Its third year now that my son is with him, I am now thinking of filing a child custody case. I want to know the average time and outcome of the case given that I have moved out of India and married again. I want to bring my son back to me at least until his college completes. Few important points to note here are that I am more educated. earn more, share good relation with my son despite the circumstances, my family is quite orthodox and won't help me here. Please suggest. Thanks