Go to Unidentified emails in the main menu. If you want to link the unidentified mail to a collection file, click on the mail and then link message at the right corner. 

Unmail 1

To link the mail to a debtor you should look for the file as below:

If you want to search the debtor by name, do not check the box. If you want to search the debtor by case number you should check the box. 

Unmail 2

If you found the debtor with the linked files, choose the file that belongs to the unlinked email.

Unmail 3

Now choose if you want the email associated with the debtor or the client. 

Unmail 4

You can see now that the email is linked to the profile in the activity panel of the corresponding debtor.

Unmail 5