You should have expressed in writing the reasons for your decision to resign in your notice of resignation and should have addressed the notice to your appointing authority, MD/CEO, Company Secretary, with a copy to Head-HR. You should have mentioned that you were subjected to rude and tortuous conduct and made to work for day and nights ( mentioning reporting time for duty, and clocked hours, breaks if any, exit time from work station, exit time from office both separately, and other data which shall prove that you were on the job from time.........to time on each day e.g. chat record, email record, SMS , time recorded on start and end of assignment/task/project etc. anything and everything) and you had represented ( even if verbally) to Mr/Ms.........designation............dept........that it is inhuman. This could have given you weightage and handle to negotiate and provided evidence that you were coerced/ forced to work overtime without any extra wages and might have helped you to claim OT, and provided crucial evidence to establish employer is unworthy of being employed with. You should have mentioned that only routine work may granted to you on day to day basis during notice period and opportunity may be given to you to prepare and firm up your exit process and settlement dues.
You should have concluded subsequently by letter that the conduct worsened to unbearable after you submitted notice of resignation (and you have no other option than to stop coming to office, or proceed on leave, and company may waive off the notice period.) You should not have absconded. You could have submitted sick leave application.
Employee should not leave opportunity to build record and keep copies. Now the company won't let you have access to bio metric attendance, on line attendance and any other record.
Employers are known to chase the employee, to deter others . Company can charge the employee for having caused the loss. The loss has to be proved.
It is felt that you may approach a reputed, competent and experienced service lawyer, who appears from employee side, with all record you have, give inputs in person, and let your lawyer structure and draft a fitting reply. Your lawyer may advice you to wait till company issues legal notice. In the meantime you can weigh your options.
Some lawyers prefer only employer side cases.
Software companies do plead and at time have situation where employee should be at the workstation to attend ongoing projects. When the notice of resignation is served upon the company should act at once and designate a replacement and in case employee at similar designation is not available reporting authority/HO should be designated as replacement.