This problem might arise if the bill in question depends on device association rather than owner user ID.
Users should be associated to phone extension through device association in order to be listed in the Call Detail Record (CDR) user reports.
The bill per user depends on the association of a given phone with the corresponding user ID. The new members of a department could have this detail missing.
For CDR records to be associated with an extension, go to User Configuration page and associate to phone extension through device association. Remember to reset the device after making the change.
The new calls are associated in the CDR record to the person s ID, and they become visible in the billing reports that require user ID input.
Old calls are not be affected by the change, as the CDR records are already written for them.
For more information, refer to the Configuring Department Bills section of CAR User Reports Configuration.