I want to file an fir on girl name nilam maker on Instagram she abuse my family and saying prostitute to my sisters,mother and also blaming me that I stalking one girl on function but i don't do anything and if I don't do anything who the hell she is to blame me or saying my mother and sister prostitute helo me sir to file an fir on her
You can file an FIR at your local police station. An FIR must be filed at the police station closest to the location of the crime. No police station can refuse filing of an FIR. Please note that every police station has a jurisdictional area within which they may investigate offences and crimes committed.
Section 79 of the IT Act provides a safe harbor to intermediaries against any act of cyber defamation. Section 79 provides that an intermediary (in your case, Instagram is not liable) is not liable for third party information, data, links hosted on its platform. However, the safe harbor protection is limited to certain conditions viz. an intermediary shall be liable if it initiates the transmission of such defamatory content, selects the receiver of such content or modifies such content.
If that girl is saying all these things in public then she is committing a crime and she is not supposed to do that. You an very well go to the nearest police station or cyber PS and lodge he complaint.
You can directly go to the Police Station and try to convince them and get register a criminal case against her by showing all the evidences that you have.