Absconding from job

I was an intern in a software development company with a monthly salary of rs. 15000, this was my first job and I was searching fir a good job as well, I got a very good opportunity and they wanted me to join within a week. I talked to my HR and told him that I have got a new job, what should I do? He said that talk to your mentor if he permits but my mentor refused because of the fear of boss. I had no option other than absconding the job. I stopped going to office from the next day. Last month they sent a letter that pay a penalty of rs 75000 and come back. Now they have sent a legal notice at my home which says that pay a penalty of 175000 otherwise we will take you to court. According to the employee agreement I was told to serve a notice period of 15 days as an intern before leaving but at that time the HE had told me verbally that if you want to leave you can compensate your salary as well. I left my one month's salary to the company and sent a resign through mail. Do I need to worry about the legal notice or not?? Please help.