Credit card default

Hello, I was using SBI & HDFC credit card between 2012 to 2014.. I've always made on time payments.. Never missed any.. But due a natural disaster, my shop electronic goods were short circuited and this pushed me into a financial distress.. At this very time when i was financially weak, my wife divorced me.. She left my son with me as she had no intention of growing him... This further pushed me into mental distress.. It has been 6 years.. I had already made settlement for HDFC bank as the settlement amount was only 10k.. I sold my bike to make this settlement.. Right now, I'm working in my brother's shop on a daily basis wages of rs. 300... I've currently not made any settlement for SBI as these guys are asking me to pay 1.2laks inc of interest.. However, the original amount was only 70k.. I don't have a home / vehicle / any asset... With this rs. 300, I'm paying 2k/month for my son's education.. 4k for food for my son and myself.. And balance money i pay as a share of rent for staying with my parents.. I've even explained this to the collection people but they're not understanding anything... They're only talking about the money i owe... Finally they threatened me tat they'll file case against me... So i asked them to proceed as i dont have anything or anywhere to go... Please let me know what i shuld do in this circumstance... Thanks in Advance..