If you want to automatically reject calls from specific phone numbers, you can do this easily on the Polycom Phone. Here are the steps:
1. Go to the Menu (Each model may be different see the guide for your model)
2. Choose Features
3. Select Contacts Directory
4. Click on "Add"
5. Enter the contact info and the numbers you would like to block.
6. Make sure to set the Auto Reject to "Enable"
Now when someone calls from that number your Polycom Phone will not ring.