The ISN has a setting that allows you to enter an alternate email address to be notified in the event an email bounces.
Navigate to Settings -- Office Settings -- Interacting with my Clients and Agents -- Email Template options:
Click on the setting that says When an email event bounces, use a different address to send the bounce information, enter an email address into the field that pops up, and click Save Settings
If you have any questions about this process please let us know! You can reach us by chat, email at firstname.lastname@example.org, or phone at (800) 700-8112.