To be completely fair to the OP, this is right from the site:
Originally Posted by https://my.vannicholas.com/configurator
ADVICE WITH YOUR FRAME SIZE
Need help determining the correct frame size? Get advice from Van Nicholas. To determine the final frame size we recommend you to get in touch with a Van Nicholas retailer.
Emphasis mine. When I punch in my size into the configurator, I come up with 47cm, which is a bike that I would never consider to be my size when buying a road bike. It appears they may use a MTB sizing system, which would understandably toss folks off, which the dealer (IMO) should have been fully aware of and able to advise on.
That all said, I presume there was a purchase order you agreed to. Once again (and once again, all of this is IMO) the bike is yours. IF the dealer is willing to help you out with a fair value trade in on a smaller frame bike, or maybe offered free labor to transfer parts over to a smaller frame you purchased, or perhaps sell the bike for you fee free on consignment, that is about all I could expect out of them. If this were a common, off the shelf bike they regularly stock my answer would be different, but the reality is you are dealing with a high priced special order that may take them a while and a substantial discount to move.
I don't know how the legal system works in the NL, but in the US you'd pay enough and eat up enough time in court that even for such a bike, it wouldn't be worth it to me. Unfortunately, this is a live and learn situation (again, IMO).
Sexy looking bike though
