Tired of getting pestered by people you don't want to speak to? Then you could turn to CallGuard to help you out.
This Symbian application allows you to filter out unwanted calls based on a black list/white list filtration system. When enabled, incoming calls from any of the numbers on the customizable blacklist will be automatically rejected by your phone. So you could add known cold callers, ex-partners or even your boss to the list.
The white list is a list of numbers that the phone will accept calls from, and if it's enabled it means that only calls from these numbers will get through to you. Editing the white list (and the black list) is very easy, and CallGuard gives you the option to import your phone contacts into these lists.
CallGuard is very customizable, allowing you to schedule time periods where the program is active. You can choose between three different call rejection actions - silent, busy tone, or send an SMS to the incoming number notifying them that they've been blocked.
Unfortunately, CallGuard doesn't allow you to block SMS messages from certain contacts. If you want this functionality too, you'd be better off with Advanced Blocker, which can reject both calls and text messages.
But if you want a simple, no-fuss way to stop nuisance calls, CallGuard provides a reliable solution.