If you're receiving nuisance calls from a particular number or set of numbers on your PBX as a Service, you can apply a custom route to filter these calls to voicemail, a particular extension, or disconnect when the call comes in.
To create an inbound filter, navigate to the PBX web GUI (https://neural.zendesk.com/hc/en-us/articles/200598895-PBX-as-a-Service-Configuration), then select DIDs from the left hand navigation menu and edit the DID the nuisance calls are being received on.
In the edit DID options, show Advanced Options and select CLI Validation & Routing.
Select Add Rule, then populate the fields as follows:
Caller ID: Enter the full callerID of the nuisance caller, including the area code (eg. 0212345678). You can also enter a partial number to block a range of numbers (eg. 021234567)
Destination: Select the type of destination you wish to have the call routed to. Deny Access will immediately disconnect the caller.
Value: Enter the ID of the destination you selected above (eg. 101 for extension 101). This field is not used for Deny Access
Match Explicitly: If you've set a partial caller ID in the Caller ID field, to block a range, set this to no. Otherwise, set this to yes.
Finally, review your rule from the CLI Validation & Routing overview screen. You can edit or remove the rules from here, or create additional rules as required.
Once all your rules are in place, close the popup window then single click the reload button at the top right to apply your changes.
While it is possible to block anonymous callers, this will reroute all calls that do not have a caller ID present, not just the nuisance caller. Therefore it is recommended that if creating an anonymous rule, a destination other than Deny Access is specified.
To create a rule to filter anonymous calls, enter the text 'anonymous', without the quotes, into the Caller ID field in the rule creation dialogue.