A service on the estate record that is not on the billing file: ceased and never removed, or ordered and never provisioned.
A ghost service is on the estate and not billed. The two usual reasons are opposite: a circuit that was ceased and never removed from the record, which makes the account plan and the renewal quote wrong, and a service ordered and not yet provisioned or billed, which finance wants to know about. Each ghost is one row with an owner.
Services on the estate record with no matching line on the billing file, by service reference.
A 100 megabit circuit at one site was ceased six months ago and is still on the estate. The account plan and the renewal quote both include it.
Found at renewal, when the quote is wrong in front of the customer.