The DemoUnit app is an internal Apple company app and is not available to the public. So where did you get it? The screenshot clearly states the device is the property of an Apple Authorized Reseller.
The only way you might possibly (but highly unlikely) resolve this is by taking the device to an Apple Store or authorized Apple service provider along with your original purchase receipt showing the serial number of the device.
Otherwise you are out of luck, up the creek without a paddle, behind the eight ball, or any other colloquialism you can think of.
And no one here will lift a finger for you, period.
No one here is an Apple employee or Apple contractor, just fellow users. Take this up with the Apple Support team. Open a ticket and see how far you get.