Just a guess, but I'm pretty sure they'll refund anyone who paid too much because of this mistake.

My bank blocked aliexpress and needed a phone call before the first time I could buy there, but not fxtec. Credit card companies are overly cautious about anything not a big established business outside of the country where the card is from, this isn't fxtecs fault and probably also only affects a minority of customers most of which can fix it with a phone call. Selling via another platform would probably add to the cost and is not a sensible thing to do for pre-orders, I do hope they will manage to have big online retailers sell in the future as that'd help their success .

On the subject of third parties selling Pro1's, I spotted this some time ago, no idea if it's legit: https://www.clove.co.uk/products/fxtec-pro1