Windows licence problem

To follow up the absence of a warranty on the laptop I bought from Bluetech in September 2019, I discovered recently that the Windows licence is no longer valid. It appears that Bluetech is using a form of Windows licence that needs to be refreshed annually. I presume they would not charge for this but it's still a nuisance and certainly not the usual way of doing things. I'm happy to accept I got a good price on the machine - but they should have told me about the absence of the warranty and the non-standard Windows licence.