Child maintenance

Hi My husband and I were living together about 16 years ago in the US. After a very difficult period for many reasons. I came to India pregnant and had my 2nd child here. Both my children are now 16 and 19. He and his family played some games initially but then he lost interest and disappeared about two years ago after much begging he agreed to sign my younger child’s passport and so now my daughters are US citizens. I got custody of both my children and a divorce decree by default as he didn’t show up in the Chennai courts awarding me 5 crores as per the divorce decree which of course I never saw. Custody of my children came with no maintenance order as my husband had stolen from a bank and was facing criminal charges that he was convicted of and sent to prison. He was released from prison and on bail for 5 years during this time he married the woman he was having an affair with and proceed to have 3 children with her. About two years ago when he reappeared in my life after signing my younger daughter passport papers he started sending in a minimal contribution of 50k every few months. Always followed by a nasty email as to how I took his kids away and how he got married again and had three more kids to get over the grief. My children want little to do with him and he feels I have poisoned them. I didn’t his behavior did but he is not capable of seeing this. I honestly feel exhausted and want him just gone. But I work very hard to support my children but my children now feel I should fight for maintenance from them. They feel entitled to it. Please let me know what my rights are. I want to give my kids more and I feel I could if he contributed. Please let me know what my rights are.