API : Deleted customers

A deleted customer is not removed from the database. It is kept with state DELETED and deletedAt set, together with its invoices, its users (stripped of personal data) and its change log. These endpoints let Telecom X staff look such a customer up, for example when finance needs to see what a customer that has left had. Everything is read-only.

Access level is RESELLER_ADMIN or ADMIN for all of them. Every endpoint with a CUSTOMER_ID answers 404 unless the customer exists and is deleted - active customers are looked up through Customer.

Deleted customers
List	Deleted customers, newest deletion first, with an optional filter.
Get	A deleted customer, who deleted it, record counts and its change log sections.
Users	The users the customer had.
Numbers	The phone numbers the customer had, with the SIP or MVNO account each one was on.

The invoices and the change log of a deleted customer are read through the usual endpoints, which accept a deleted customer for RESELLER_ADMIN and ADMIN:

Invoice list (customer query parameter) and Invoice get, including the CSV export and the PDF.
Change log list and Change log get.

How far back the history goes:

The customer, its invoices and its users are kept in full.
The change log starts on 2022-01-24. Customers deleted before that have no deletion entry, so their deletedAt is 2022-01-24 (“deleted no later than”) and who deleted them is unknown.
Phone numbers and SIP/MVNO accounts are rebuilt from the change log, so they too go back to 2022-01-24.
CDRs are only kept for about a year.