Please follow Section 3 in the revised manual:

Here are some important tips:
1) Make sure the handset(s) making outgoing calls is(are) connected on the PHONE port of the call blocker.

2) Make sure you enter all the digits when adding numbers to the call blockers (following Section 3), including the leading 1, if necessary.  Note: If your local area allows both dialing plans (with or without 1), make sure you program both into the call blocker.

Still not working?  
If after you follow the above steps and tips, your call blocker is still not blocking outgoing calls, there are 2 possibilities:
1) Your call blocker is defective.  
One way to detect if your call blocker is defective is by testing if the BLACKLIST feature works.  To do this, after installing your call blocker, call your landline from another phone e.g. cell phone. Then while the call is ringing, press the BLACKLIST button to add the number to the BLACKLIST.  If the call gets disconnected, then that proofs that your call blocker is in good working condition.

2) There may be a compatibility issue with your phone service.

Compatibility issues are harder to identify.  One way you can do this is by testing your call blocker using a different phone line (maybe taking it to a friend or neighbor's house).
You may also consider another Outgoing Call Blocker.  Please check our other Outgoing Call Blockers models.