When you enable auto reject feature on your Galaxy device, it automatically rejects the numbers you have added to the list. Auto reject calls on Samsung Galaxy devices is activated by doing as follows:
1. Open Phone application
2. Press Menu Button and then select Call Settings
3. Tap Call Rejection to manage auto reject mode
4. First make "Auto Reject Mode" is enabled (turn it off to disable auto reject mode) and then tap "Auto Reject List"
5. Now use the Plus icon to add phone numbers to the reject list (you may use the match criteria option to reject calls, starts with, ends with, or includes specific numbers