Howto
From x164 documentation wiki
Set up DIDs
Set up customer profiles with prefix dialing]
Establishing usage quotas for users]
How do I limit the usage of a subscriber per month?
This can be done from the 'Quota usage' table. There you will find an entry for each customer and carrier included in the database. All you have to do is update the 'Quota' field of a record. When the count in the 'This Month' field exceeds the quota, the 'Notified' field is updated and the subscriber (customer or carrier) is blocked. This means the system sets the 'Blocked' field of its corresponding entry in the 'Customers' or 'Carriers' table. To unblock a subscriber simply update this field with a '0'.