To remove your phone number from TrueCaller database,
1. Goto http://www.truecaller.com/unlist
2. Enter your phone number in the field provided, including your country code, i.e., if you are in India, enter +91 followed by your phone number. The phone number may be your mobile number or landline number, which ever one you want to be unlisted.
3. Verify the captcha code to proove you are not a spammer/bot.
4. Click on "Unlist" buton.
If the information is correctly entered, your number will be instantly removed from the true caller database(previously it used to take a day or so). Repeat this for each number you want to be unlisted.
If truecaller encounters any error in the number format you entered or if the captcha doesn't match, it will display an error. Correct the information and click unlist again.