This information can be found in the logs of your SUPPRESS account. There are several different types of logs available in SUPPRESS, but a common one to review in this case is the Mailer logs - this will show you the activity of a specific Affiliate/Mailer.
To view a Mailer's log activity, follow the steps here: How do I View the Activity of a Mailer?, then scroll down to the bottom of the page.
An Affiliate/Mailer has successfully downloaded a Suppression List/Opt-Out List when you see the following two log entries.
- prepared a download: will let you know the Affiliate entered accessed the Campaign and triggered the action to get the Suppression List ready.
- downloaded the suppression file: will let you know the Affiliate has downloaded the file from our servers
If you have further question, please contact us at: firstname.lastname@example.org