How can I file a defamation case against with my...

In the event of an offense punishable by law, you can file a complaint through:
1) Writing a report at the police station
2) Submit a complaint directly to the Public Prosecution
And if the crime did not occur on you personally, then you are called by law a notifier and you benefit from something called the whistleblower protection system, so that your personal data and your place of residence cannot be disclosed, and you are considered a witness in the case with the criminals signing a pledge not to harm you in the later stages of the investigation