We sell items to and issues invoice to Customer A but Customer C pays it. Customer A and Customer C are not parent-child and related entities. How is this being handled in NS?

Create a Journal to DB cash and CR a custom liability account for the payment from Customer C. Then post a credit memo (applied to the Invoice) for Customer A that DB the same custom liability account and CR A/R OR Create the Invoice set to Customer C but make the Ship To and Billing address to Customer A