Employment bond

Hi! I am a 23 year old female. Completed my MBA. While joining an organization as a Management Trainee, I was asked to sign an employment bond for 2 years (which includes 6 month on-job training) on a 20-Rupee agreement bond papers. And because I was desperate for a job, I signed. And my father signed it as a guarantor (on a printed sheet). I worked there for 3 months. I was shifted to a new department. I was said that my work timings will be 10 a.m to 7 p.m. But every day I left only after 7, worked from home, worked on holidays and it was becoming a pressure. There was no safety concern as well. So, I quit the job without any notice(scared of the bond). I received couple of phone calls and my mom responded them that I was not well and my work was becoming hectic at the work place. Then I joined another job. After a month, I received a letter from them to report. But then I didn't respond. Now I have received a legal notice from their lawyer quoting I am employed in a similar organization, and they need a compensation of 10 lakhs from me and my father. The total salary paid by them was INR 35,000 for 3 months and demand a sum of 10lakhs. Above all, it was not on-the-job training. I was made to work day and night for long hours. Can you please help me on what should my next step be?