Clickbait, when attempting to check your data you are requested to login, where they auto check "Enhanced Search" which states: "By enabling Enhanced Search, your contacts are securely shared with Truecaller. This improves accuracy of your search results and helps improve the experience for millions of users around the world." - Simply by logging in you are giving your information away.

I was surprised that my personal data was leaked and I found my name and number listed in this website.

They get people to share their contacts from gmail and then show your data

In case you find your number listed, unlist here

Unlist | Truecaller https://www.truecaller.com/unlist