OK. I don't have the service.
support@voipo.com with that info would get a quick response I expect.
I would think if its a Residential Account, that its included in the basic fee.

If this is a main Reseller Account, the connect time may be billable even though a DID and service functionality is included.

Similarly, a toll-free DID is included with a Reseller Account, but the minutes are billable.

Emailing support will should get an answer. You can perhaps update us here with the gist of answer so we can all learn.