You may simply login to your Truecaller web account and select the ‘Deactivate your account’ option from the Account & Privacy menu.
For any further assistance you may need, please reach out to us on support.eu@truecaller.com if you are in the EU/EEA/UK or support@truecaller.com if you are in any other country.
Please note that it may take up to 24 hours before your entire information gets deleted from our system.