Depending on how the mailbox is installed in iController, the email address linked to the entity to whom the debtor belongs OR the default mailbox installed in your user settings, is used.
When there is an email address filled in the field 'email' in the 'company details' settings and the mailbox is correctly installed in iController, this mailbox will be used for communicating with clients belonging to this company. When this is not the case, the default mailbox installed on your user account, will be used.
Please contact collections-support@billtrust.com to make the desired setting changes.