How to catch a person who is orally harassing and lying?

Dear sir/madam,

How can you catch a person who is harassing and lying to you orally and also using abusive words?

He does not rely on text, email, or WhatsApp. Audio or video recording is a crime in Dubai though it is for personal safety and is not shared with anyone on social media.

If we ask for consent, he will never give so it is a win-win situation for a false person & not for a true person in Dubai, where we can't prove oral communication.

This rule is a big win for those who are false orally & ignore you on email & WhatsApp.