threatened to killed, obstruction in performing government dury and violation of pandemic act by forcibly standing on gate without Mask

It is the duty of concern of police / court to take cognizance of accusation under appropriate provision of Indian Penal Code, 1860, if it existed based on facts of the complaint. 

The duty of a citizen is to narrate facts with such date, timings, names of persons etc., and it is left to the investigating officers to register the complaint with such sections.   Police need no suggestions from citizens.  If Police is not cooperating you may file an online complaint and if no action is taken file private complaint.   TIll then maintain a record of events in your own handwriting and take enough precautions for you and your family's safety.  You can also report the matter to your superiors so that they can take up the matter with the police as you are prevented in performing your duties.

If police is not registering FIR then file private complaint before magistrate.  Then magistrate will take cognizance of the case and direct police to investigate the matter.

You can send your complaint to the higher authorities if F.I.R. not registered. or else approach local courts for filing a private petition in the court. Whoever assaults or threatens to assault, or obstructs or attempts to obstruct, any public servant in the discharge of his duty as such public servant, in endeavoring to disperse an unlawful assembly, or to suppress a riot or affray, or uses, or threatens, or attempts to use criminal force to such public servant, shall be punished with imprisonment of either descripttion for a term which may extend to three years, or with fine, or with both.