The iATS Nightly Download scheduled Apex Job retrieves Transaction and ACH Return details from iATS processed the prior day. To delete this job:
1. Enter Salesforce Setup:
2. In the quick find search box, search for scheduled jobs and click on the resulting item. 
3. Delete the job with the Job Name "iATS Nightly Download" schedule job.
Instructions for re-enabling this job will be provided at a later date.