Do API calls to the /Communication endpoint work or not?

As documented:

get https://yourorgsite.com/api/Communication
Returns a list or single record of Communication
https://developer.imis.com/reference/getcommunication

A call to /api/Communication returns 400 Bad Request. A GET call to /api/CommunicationLog works, as does a GET call to a specific communication log: /api/CommunicationLog/e087b113-d2d1-4a39-acc4-4bde3832fb6a. But a DELETE call doesn't work on that same endpoint, nor to /api/CommunicationLog?CommunicationLogId=e087b113-d2d1-4a39-acc4-4bde3832fb6a. I'm trying to keep the communication log clean, 25% of the log entries are for 0 attempts, hence 0 need to keep the communication log component. There should be no need to delete from the other 2 tables - recipient or event - there's nothing in there for an empty communication (no attempt made).

What endpoint should I use? Thanks.