In IG go into your IG certifications and \Administration tab. Click "Escalation Emails" button on the \Administration tab (at bottom, you will see the button behind the "Escalation Emails dialog"
In the "Escalations Emails" dialog you will see the "Stop Scheduled Emails" button at the top or or it will say "Scheduled Emails" which means it is not stopped. Click "Stop Scheduled Emails" is available.
From the \Administration tab, click on "Disable Email"