Step By Step
1. If it is installed in your android phone, Go To Menu >> Setting >>About >> Deactivate.
2. Finally uninstall the app.
Another method, you can do it by visiting their official website truecaller[dot]com.
1. Go to https://www[dot]truecaller[dot]com/unlisting
2. Select your country.
3. Enter your phone number which you want to remove from truecaller database.
4. Select check mark I'm not robot.
5. Finally, click on UNLIST PHONE NUMBER. That’s all.
You have to wait for at least 24 hours to update the database.
Please. remove [dot] from URL to reach to the actual URL