Resignation during bond period

Currently am working in a company of 3 years service agreement signed with lieu amount of 3lakhs rupees if bond is broken. Right now am feeling so much stressed and pressurised by the job and want to quit the job. I am also having medical issue in which i took medical leave for one month too, still i am unable to continue due to the stress and my health issue. I talked to my HR regardingly but he was harsh on his approach to me stating that "you draft a mail to the management and face the legal consequences that needs to be done". Its been 1.5 years am working for this company, still 1year and 9 months remaining. They dont have any of my originals with them. I want to quit this job, i am unable to continue in this job. How should i need to approach the management via mail? Will they send a legal notice to me? Or should i need to pay 3L if i need my experience certificate? Or should i need to abscond or just relieve the company conveying to them?.... What should i need to do.. Pls give me a solution for it.