Do i need to work in notice period if the work is hard to understand for me which is the reasonation

Hi, I joined on 30th june as a fresher, from 20 of july we started training which was for 7 weeks and then we come to the Ramp (THIS IS ALL WORK FROM HOME) where we do our Task with weekly increasing , because i unable to complete my target and work is hard to understand for me I have resigned on 30-Sep-2020 , i raised this things upto TM and SDM that i dont understand the work completely but they are saying you have to work and complete your target with 100% accuracy (no employee in team not able to do with 100% accuracy) i said if i could do even 80% of my target then why i would resigned , i could take ratings as per 80% completed target . Then i asked for refresher training so SDM saying we could provide you refresher training for 1hour or 2 daily hour but this is your extra time than your productive 9 hour saying that you have to complete daily target with accuracy along with training there is no relax. I dont wanna give my extra time to this organisation now who force thei fresher employee. I dont want to pay for early release to that company. Because once in the mid of September 2020 when i took my mother to the relative's home who (relative suffering from illness) was suffering from illness then i dropped message to my TL saying that i could take a day off today, then he called me after 4 hours after dropping my message , he said YOU HAVE TO COME HOME AND LOGIN AND COMPLETE YOUR DAILY TARGET BECAUSE YOU COULD NOT COMPLETE YOUR TARGET AND THIS IS NOT YOUR EMERGENCY my soul was hurted that day and i had decided to resign ,(this is work from home) So when he forcefully asked me to come so leaving mother my relative's home i set out to home to complete target. I also raised this to my SDM AND TM but i dont think so they would take action against it and many type of pressure my TL gives me, So i dont want to pay this organisation for early release and i dont want any experience letter and any type of document from this company , for 3 month working. Is it necessary to do target ? If yes then I could give 30% target. Is there any chance they can go legally ? Please reply me i am in very much tension. I have no contract with the company but have 60 days notice period.