Windows 10: After resseting my pc with keep my files option, got problems with activation, it says no...

I tried to change my product key the same key and gives me a 0xc0000022 error code. I had a support phone call and the agent asked my product key. I was not sure about that but I got a call after I requested help. from the get help in the settings. official Microsoft support right ? after I gave the key, he told me that is a developer key and I cannot use it anymore and there were multiple activations. I have used 2 years with no problems why now? he told me to contact the seller to give me a new key.. its been 2 years I don't know if the seller is still active. what can I do now?

:)

 

resseting windows with keeping files

Hi i have resset my windows 10 with the first option wich is Keep my files and i was used to have before resetting 792gb free out of 1000gb with some games from Steam ,after resseting i have only schortcuts on deskotp without icon only with name of the
game and no games at all but my disk sapce was the same 792gb out of 1000gb. How are gone my games without their disk space and how can i delete this unsusable sapce?

 

My PC suddenly says its not activated

For verification, now you are saying it isn't activated and Microsoft won't help you?

 

My PC suddenly says its not activated

I wish I could hands-on your PC .... it's a bit difficult explaining stuff...