Delete a customer of a company

Deletes a customer of this company that has no invoices.

• What deleting means: the customer is retained internally for tax record-keeping purposes, but is no longer exposed by the API: subsequent requests to it return 404, and it is never included in the customer list, under any value of the active filter.
• Identifier released: its NIF or alternative identifier is freed, so a new customer may be created with the same identifier.
• Customers with invoices: they cannot be deleted and the request answers 409 CLIENT_HAS_INVOICES. To stop using a customer, update it with active set to false instead of deleting it.
• Customers used by a recurring invoice: while an active or paused recurring invoice has the customer as its recipient, the request answers 400 REFERENCED_BY_RECURRING_INVOICE.