Error 0xC004C003 after Media Creation Tool Upgrade can't roll back

Hello fellow tenforums members,

about 10 days ago, I decided to upgrade my Windows 8.1 to Windows 10 via the Media Creation Tool.
After having installed the new OS, I was greeted with a watermark prompting me to activate Windows.
As stated in the title, I get Error 0xC004C003 trying to do so, with the message that the key has been blocked.

Trying to activate over cmd does not result in anything but an error as well.

Now I tried rolling back to 8.1 by selecting the option under settings but it seems that the recovery files were somehow deleted or something after having updated 10 to the newest version..
I have no old copy of Windows lying around (bought and downloaded 8 digitally but the HDD died..
Found a note with my 8 key in a folder of mine but that one appears to be the key that Windows automatically generates (forget what this kind of key is called)..

I did check before running the upgrade and Windows 8 was activated, by the way!

So basically I have no idea how to proceed and hope you can somehow help me out

I went from an activated Win7 up to Win10 and ended with the same error code,i went here and there looking for an answer all to no avail,In the end a fellow member in here said,Bite the bullet and start over again.So after trying for nearly a week of looking for answers,i did just that,reinstalled Win7-activated it-got all the updates and after about 12 hours i got the chance to upgrade to Win10 again through the "reserve your Win10" icon.But in my case i did stuff it up totally and try to do a clean install first off instead of going through the correct way and upgrading first,thats why i got the Error Code:0xC004C003,it was never going to activate,hope this helps a bit.Might have to spend a night and start over again.