You can block calls coming to a specific number from a specific number in your Press8 Control Panel. You can add as many blocks as you need.
*** Note: To update this feature, you must either "own" the number as a user or have Administrator priviledges. If you are not the Administrator or do not own the number that you want to set a block on, then please contact your Administrator to make these updates to your account.
Here are the instructions on how to do that:
Login to your Press8 control panel: https://manage.press8.com, then go to: Devices & numbers/Numbers. Click on the number that is being called, and scroll down to the bottom area for "Caller Routes". Click "New", and enter the 10 digit telephone number that is bothering you in the "Caller number prefix" field. Add a description for future reference and either leave the "Forward matching calls to:" field as is to "Hang up call" or set another feature, like mailbox or congestion tone, for routing the call with the matching caller ID.