We am trying to setup a policy to block all USB Drives except the ones
that are owned by the company

Under USB Connectivity Control we have the following setup

Default Device Access: DISABLED

Human Interface Devices (HID): Always ENABLE
Mass Storage Class: DISABLE
Printing Class: Always ENABLE
Scanning/Imaging (PTP): DISABLE

USB Device Access Settings

Name Access Device Summary

CompanyUSB1 ENABLE Serial Number=xxxxxxxxxxxx
up to 30 more...

BUT all USBs are able to connect, not just the ones we have defined in
the USB Device Access Settings

Can anyone let us know what we are doing wrong?