Please help me to get out from this issue giving suggestions
1.What hppens if FIR files in the name of me,Is my career is over..?
First of all this is not a criminal offence to resign from the job, hence your MD cannot lodge any criminal complaint with police and no also no such complaint is maintainable for the internal issues.
You can challenge him by issuing a legal notice instructing him to restrain from giving such threat calls or else to face a case in the court for criminal intimidation and threats to life.
2.Can I complain in income tax dept.
If there is a tax evasion or if you are being forced to compile records to evade tax, you may make a complaint in writing
3.or else simply work wht ever he dictates.
If you are not willing to be employed anymore you can very well tender your resignation, nobody can force you to work agaisnt your wishes and willingness.