Anonymous Call Rejection only prevents calls from ringing into your home if the caller's line is blocked and identified as PRIVATE or ANONYMOUS. It doesn't reject calls that your caller ID shows as UNAVAILABLE, OUT OF AREA, UNKNOWN or NOT PROVIDED. That's because those types of calls don't include the necessary data and/or are being sent via equipment that doesn't support caller ID. As a result, Anonymous Call Rejection can't block those calls. Examples of calls like this include: calls from cell phone networks, calls from large businesses (call centers), operator-assisted calls (collect, pay phone, credit card, international calls).
If you need help blocking -- specific numbers or certain types of calls -- maybe a different type of calling feature will do what you need done.