When I try activating Win10 Pro, installed via OEI / OEM DVD, I get error 0xc004f050

I bought a Genuine Windows10 Pro OEI DVD; after I install from DVD, Windows10 reports that it's actually Windows 10 Home and not Windows 10 Pro.

No problem, I'll use the activation key I got off the packaging...

So I go to "Start Button > Settings > Update & Security > Activation" and enter my activation key. However, I keep getting Activation Error 0xc004f050 after I enter my valid Win10 Pro activation key.

My Question:

I feel like I got ripped off... I bought Win10 Pro but all I have is Win 10 Home. How can I make this new Win10 Pro installation register as Windows 10 Pro?

I dug this up after about half an hour of googling (quoting relevant bits below):

"Start button > left side, Settings > Update & Security > left side, click Activation > right side, click Change product key........

now enter the generic Win 10 Pro product key VK7JG-NPHTM-C97JM-9MPGT-3V66T > It will start switching your Home version to Pro version BUT it will NOT activate.

First, use the default Windows 10 Pro activation key...

VK7JG-NPHTM-C97JM-9MPGT-3V66T

Then you'll have a temporary Windows 10 Pro license. Now use your activation key off the package to get your permanent license.