The way the ‘luxury’ VED is applied / implemented will be down to HM Gov rather than VW. Complaining to VW or the dealer is unlikely to achieve a successful outcome, unless the dealer is prepared to pick up the bill for the additional VED for five years which is unlikely IMHO.
Agree with @Carl_45; the £40k threshold should increase year on year by an inflationary amount. However, by not doing this, more new car purchasers will fall into the luxury VED net so it’s not in HM Gov’s best interests to inflation link the £40k threshold, especially as its a way of generating revenue to offset the zero VED rate on electric cars.