CRM API using the GET Action to search for customers by <EMAIL> does not return any results when the query value is in all caps characters.
Example, if the email is stored in the CRM 'firstname.lastname@example.org', this does not retrieve data:
<command object="Customer" action="get">
Virtual Contact Center, CRM API
Enter the email address value in the same case as it is stored in VCC CRM.
The VCC CRM API is case sensitive when using the GET Action to search.
For more information, see the CRM API User Guide.