Permanently deletes leads and their step and reply history. This cannot be undone.

Deletion leaves no memory behind: re-adding the same address later enters the campaign fresh. To block an address for good, add it to the suppression list instead.

Up to 500 leads per call. missing counts ids that were already gone — a foreign id, or an earlier partial run — so a healing retry that deletes nothing new doesn't read as a failure. If some deletes fail the response is a 500 carrying the counts; retry the same ids to finish the job.