Controller won't pair

I posted this problem two days ago and haven't had any response, so I'll try going into more detail.

I bought an Xbox Controller+Wireless Adapter for Windows 10, model 1708,1780 for use on a Win10 PC that does not have native Bluetooth. It refuses to pair.

The Device Manager shows "XBOX ACC" present, but says there are no drivers for it. The only driver file on the Microsoft site is for Win7. I downloaded that, and it refused to load, saying parts of the driver were not present.

Trying to add the unit under "Settings->Bluetooth & Other Devices" does not show the unit.

According to the instructions, pressing the button on the adapter is supposed to turn on a blue light and start the pairing process. The adapter has the button, but there is no blue light anywhere.

I tested the unit on a Bluetooth-equipped machine, and it paired up without trouble. In other words, the unit's Bluetooth works, but its Wireless function does not.

Microsoft Support quite literally told me to go away: "This issue is not eligible for call or chat".

Can anyone offer help, or do I have to go the RMA route and forget Xbox operations until my next computer?

:)