With Handy Blacklist, you can:

• Add specific phone numbers to prevent them calling you! The unwanted calls are blocked immediately. The only way you will notice that person called you is by observing the application call log. If you disconnected a call manually, Handy Blacklist will propose you to add that number automatically!
• Block not only specific phone numbers, but private and unknown numbers as well! If you want to tighten your security even further, this function is right for you.