My previous employer threatening me to pay 3 months salary for not serving notice period

Hi, I was working in a small company for 3 months. The things were not moving well and I had a quarrel with my owner and they terminated me from the service without any prior information. Once when I tried to open my office mail it was deactivated and then only I realised they expelled me from the job, and I have formally wrote a mail to them that because of health issues I wasn't able to go to office on that day, and also I will submit the laptop to them. As said in the mail I submitted the laptop. Now after a week, they are threatening me that, with the reference to the mail I sent they framed me as an absconder and they are asking me to pay 3 months salary for absconding, orelse they will file a case on me. Since I was in probation for 3 months and after 3 months they didn't even provided me with job confirmation letter and then how come they can threaten me like this? and also only they expelled me first my deactivating my office mail accounts. Please help me regarding the issue.