Activation lock on enterprise device - Need intervention

Sounds like it might be helpful to talk directly with the Apple Enterprise team. Here are some support pages + contact information I found:

Contact Apple for support and service

--These are specific numbers listed as Enterprise on the Apple Support website.

Enterprise

(866) 752-7753

Enterprise Sales

(877) 412–7753

AppleCare for Enterprise

--If your company or institution has invested in AppleCare, this website provides the following contact information.

AppleCare

800-APL-CARE (800-275-2273)

*This is the listing for the States from Master Terms AppleCare for Enterprise v2.3 webpage. If you need another country's contact info, start here.

It sounds bad when the support team is not responding properly. I hardly hear such issue with the Apple support team because they are best.

Apple is running smaller crews due to the COVID-19 virus to avoid the spread. You may see longer delays than normal.

In order to get a device unlocked, you must provide proof of ownership. You will need your original receipt (not a photocopy) that clearly shows your name or org name and the serial number of the iPad. If you do not have this info and did not have your device registered with Apple Business Manager, you are out of luck unless you can contact the person who locked it.

As a side note, you need to make sure all corporately owned devices are registered with ABM if possible (you can register iOS, iPadOS, and tvOS devices at any point using Apple Configurator 2, but macOS devices generally must be registered at the time of purchase). You also need to make sure you have a solid mobile device management platform (MDM) like Jamf, Mosyle, MobileIron, Meraki, Fleetsmith, etc. A good MDM will allow you to remove activation lock without all the hoops.