John,

if user deletes a message it is marked as deleted first (you can check "availabilityStatus" parameter in API response) and then permanently deleted in a week.

By default API does not return deleted messages. But you can specify explicitly if you want to see deleted messages by using "availabilityStatus" parameter in message-store API request.

Also please be aware that we have retention policy and messages can be deleted automatically - see more info here https://support.ringcentral.com/article/2178.html

If a message is deleted you can still get the message information by retrieving the message store with message is .. /restapi/v1.0/account/accountId/extension/extensionId/message-store/messageId

Ref: https://developers.ringcentral.com/api-reference/Message-Store/readMessage

In response, you will get the field call messageAvalibility shows the status as delete.Message availability status. Message in 'Deleted' state is still preserved with all its attachments and can be restored.

As per here, the RingCentral Retention Management APIallows Account administrators to customize the Data Retention Policy to ensure the organization keeps less than 90 days of message data

https://support.ringcentral.com/s/article/2178?language=en_US