[skylarking]

Did QNAP ever promise kodi, or just that the nas can play media? If the latter, as long as there are applications to play media, they can change them.

QNAP advertising both on their website and product packaging itself prominantly showed the Kodi app being used
As such, QNAP's Kodi build was a 'product feature' which may have be reason enough for many to chooses QNAP NAS's over some other competitor
For QNAP to remove the Kodi app apost sale is very much like a delayed bait and switch tactic and would be a no no in most jurisdictions

So if you've been stung by this behaviour, i'd recomend you make a formal complaint to QNAP and then to your local consumer protection group should they do nothiong.
Hopefully with such formal complaints to a consumer protection group (is some jurisdiction) QNAP is jumped on and heavily fined and forced to behave more appropriately and legally in future

PS: workaround for getting Kodi back are only a temporary fix as i think it's better to stop such 'delayed bait and switch' behaviour from occuring in the first instance.