Under the Indian Evidence Act, Section 65B(Section 63 of the Bharatiya Sakshya Adhiniyam (BSA), 2023.), electronic records like voice notes, screenshots, and WhatsApp messages are valid in court if you produce them along with a 65B certificate (which can be obtained later during proceedings).
Even without the certificate, police can seize the mobile and verify authenticity.
If the local police refuse, you have the right to file a written complaint and demand a written acknowledgment. If they deny registering an FIR, you can approach:
Superintendent of Police (SP) under Section 154(3) CrPC.( Section 173(3) of the BNSS)
Judicial Magistrate by filing a private complaint under Section 156(3) CrPC(ection 175(3) of the Bharatiya Nagarik Suraksha Sanhita (BNSS) 2023).
The voice messages and photo are valid evidence.
You can file a case under IPC + IT Act.
The police cannot just refuse saying “no valid evidence”. If they still don’t act, escalate to SP or file directly before the Magistrate.

You can file a criminal complaint against her under various sections of BNS 2023 depending on the actual things stated by her

1. An offence of criminal intimidation under Section 351 is committed. You have irrefutable electronic evidence against her. File a criminal complaint  in the  Court of Magistrate  as the  offence is non-cognizable. Punishment  for offence is imprisonment of two years.
2. You can also file civil suit claiming damages against her.

If police refuse to lodge FIR file private complaint before magistrate to direct police to investigate and submit report 

Case of defamation and criminal defamation is made out 

audio recordings are admissible in evidence 

Section 79,351,etc depending on specific allegations committed by them 

Section 351 of the Bharatiya Nyaya Sanhita defines criminal intimidation as a threat to harm a person's person, reputation, or property to cause alarm or force them to do something they are not legally bound to do or omit something they are legally entitled to do.

Voice messages and WhatsApp photos qualify as electronic records under the Indian Evidence Act, 1872 (Section 65B), provided they are produced in their original format with a proper certification for admissibility in court. These records can be used as evidence to support claims of threats, insults, or defamation.

Criminal action can be initiated for the conduct described. Relevant sections may include Section 506 IPC (criminal intimidation), Section 509 IPC (insult to the modesty of a woman), Section 500 IPC (defamation), and Section 67 of the Information Technology Act (obscene or harmful electronic communication). Depending on the content and intent, Section 505 IPC (public mischief) may also apply.

It is the responsibility of the police to register an FIR if a cognizable offence is disclosed and valid evidence is produced. If the police refuse to register the case, a complaint can be made to the Superintendent of Police under Section 154(3) CrPC, or a private complaint may be filed before the Magistrate under Section 200 CrPC. Retain the original voice messages and photos, back them up securely, and prepare a Section 65B certificate. Screenshots and date-stamped records should be preserved. It is also advisable to consult a local lawyer for ensuring proper preservation and presentation of evidence and to request a written statement from the police if they refuse to act.

Yes ,the voice messages and photo are valid electronic evidence under Section 65B, Indian Evidence Act, 1872 (as amended). You can absolutely file a case. What your cousin did amounts to multiple criminal offences.

Offences applicable under BNS, 2023:

Criminal Intimidation (threats to ruin life, cause harm) :-Section 351 BNS.

Insult to modesty of woman (insulting/abusive words/gestures towards your mother/sister):-Section 79 BNS.

Defamation (false allegations harming reputation):-Section 354 BNS.

Harassment/Threats through electronic communication :-Section 356(4) BNS (criminal intimidation using electronic means).

If content is obscene/indecent:-Section 67 IT Act still applies (IT Act not replaced).

Evidence under Bharatiya Sakshya Adhiniyam, 2023 (BSA):

Section 61 BSA:-Electronic records (voice notes, WhatsApp messages, photos) are admissible in evidence.

Section 63 BSA:-Requires a Section 65B-style certificate for electronic evidence authenticity

Procedure under BNSS, 2023:

Section 173 BNSS:-You have the right to get FIR registered.

If police refuse, you can escalate to SP under Section 193 BNSS.

If still not registered, file a private complaint before Magistrate under Section 223 BNSS.

In a police complaint you don't have to include any section of law, the complaint should be proper enough to cover the maximum sections. 

If you are filing a private complaint then you can include the sections pertaining to criminal intimidation, defamation, harassment, threats and any other section which will define your complaint.

You can take the assistance of an advocate to draft a private criminal complaint.

Dear Client,

The WhatsApp voice messages and photos you have are valid electronic evidence under Section 65B of the Evidence Act, and based on what your cousin did insulting your mother, threatening your sister, making false allegations, and using an old photo to intimidate you can seek registration of offences under Section 500 IPC (defamation), Section 503/506 IPC (criminal intimidation), Section 509 IPC (insulting the modesty of a woman), and if there is repeated harassment, even Section 354D IPC (stalking), along with provisions of the IT Act; if the local police refuse to register the case, the next step is to escalate the complaint to the Superintendent of Police under Section 154(3) CrPC or file a private complaint before the Magistrate under Section 200 CrPC so please be assured that the conduct is punishable, your evidence is legally admissible, and you do have remedies to act against her.

I hope this answer helps, for any further queries, please do not hesitate to contact us. Thank You

- As per Section 65A of the Indian Evidence Act, 1872 , The contents of electronic records may be proved in accordance with the provisions of section 65B.

- Further, Audio recordings or messages are admissible as evidence, if they appear to be trustworthy, genuine and have been corroborated by other evidence. 

- If the police refuse to lodge an FIR against that lady then send this complaint to higher police official and also to the cyber cell 

- Further, if no action then you can file a complaint before the judicial magistrate in Court. 

Yes, you can file a case. The acts amount to criminal intimidation, defamation, and insult to the modesty of women under IPC, and also offences under the IT Act. The WhatsApp voice messages and the photo are valid evidence in law if produced with a proper certificate.