Company not releasing original documents what can I do

Am 7 years exp and joined a company in India which stated "you are required to stay with the company for 24 months", I resigned before my contract period ends at 1.3 yrs due to heavy work pressure, till late evening work all days, not able to take care of my child and ill in-laws. Have sent resignation mail stating from . (3 weeks time) date I will not be able to come to office, there was no response from their even after repeated reminders, finally hr informed he can relieve me only after recruiting a new resource which might take 2 weeks or 2 months or 6 months that he cannot commit and he started threatening me to work, after 2 days I didnt went to office. They have my original certificates, have not credited my salary, not provided relieving letter. Now they are claiming they have loss in their project and they want me to pay some amount (I have informed them well in advance, and they have not acted upon that). Notice period 45 days and i worked for 30 days after sending resignatio