You can tweak settings on your LG phone to block unwanted calls. When you change your settings, calls from numbers outside of your address book will be automatically sent to voicemail. The blocked caller will be unable to reach you until you change your settings to allow his calls once again. The LG phone's call-blocking feature is built-in and it is free to use.
Press the Menu key on your LG cellphone and click "Settings."
Click "Security" to view the restriction settings for your phone. Some LG models require you to click "More" before selecting "Security."
Click "Restrict and Lock" and enter your four-digit lock code. By default, the lock code is either "0000" or the last four-digits of your cell number.
Click "Restrict Voice," then click "Incoming Calls."
Click "Contacts Only" to restrict incoming calls to only callers who are saved in your LG phone's address book.
Press the Menu key to save your settings.
Mobile carriers such as Sprint and AT&T Wireless offer call blocker. Contact your mobile carrier for additional information on pricing.