That email would be fine if they were just discontinuing a feature of their ongoing service - it's disappointing, but you got value out of it while you were paying for it and now we're stopping and won't charge you any further.
But this is a stand-alone piece of hardware that they sold without an explicit expiry date, in a product category (car audio) that generally lasts decades (as they are solid-state devices with no moving parts) and now they're outright making it useless 2 years later without any refunds.