Let me see if I can explain the intended purpose of
3CX Enhanced Billing Codes (EBC), and then we can discuss whether it would work for you.
Take the example of a law firm that bills for their time. Before they make an outbound call, they must first enter the account code associated with a client. Then EBC monitors the length of the call and records it in a database. At the end of the month, a report is run that lists all the calls (grouped by account code) and a cost is calculated for the customer. We do enable you to put some restrictions on the account code. For example, you could block international phone calls when using a specific account code.
Let us consider another example. Suppose you work for a large governmental organization where each department has their own budget for phone calls. You could require the caller to put in their account code (department) before making an outbound call. Then you put general restrictions on the department.
What EBC does not do, is associate a list of numbers blocked/permitted by account code.
In contrast,
3CX Do Not Call (DNC) is intended to protect an organization from call center agents inadvertently calling someone on a national Do Not Call list. You can apply the restriction to specific groups and enter exceptions to the rules, but the list of blocked numbers is essentially the same for everyone. Also, with DNC you do not have to call a CFD and enter the phone number, rather, you simply dial the number and DNC rejects the number automatically.
If you want something different than both EBC and DNC, we can discuss a custom solution.