Sounds like they're about to get sued by the EU because they're basically asking you to pay again for a product you have already paid for. Discontinuing a service that was advertised as the "last windows you'll ever need" is one thing, but sending you another bill on a whim is something entirely different. Microsoft might just have ensured the longevity of Win10 for the foreseeable future without making much if any profit from it.
Requiring a support contract to receive continuing updates of software that was very publicly approaching end of support, with published EoL dates for years now does not break any laws.
By that logic, no support contracts are legal in the EU at all, and no product would ever be sunset.