License purchased thru Store is tied to hardware used for purchasing, this is why you did not get a product key. The Store sends an information about your purchase directly to the activation servers so there is no need to use a key.
Store says before purchase that this license is tied to hardware, but this is not evident enough unfortunately.
I deeply sympathize with you, but alas, this is Microsoft's policy.
However, you may ask Microsoft support for the help with activation. [ https://support.microsoft.com/contactus/]
Note: guest virtual machine has another hardware than host system. You may compare information provided by msinfo32 tool.