Cancel a pending scheduled inbox reply
Inbox
Cancel a pending scheduled inbox reply
Flips an inbox-originated scheduled message from scheduled to cancelled when scheduled_at hasn’t fired yet. 404 if the id doesn’t exist or the message is already past the scheduled gate (queued / sending / sent / failed / cancelled). No billing refund — billing is debited on the send-path AFTER the scheduler dequeues the row, so a still-scheduled message has no balance charge to refund.
DELETE
Cancel a pending scheduled inbox reply