First, it's probably a mistake (on the part of their supplier or an employee), not deliberate policy.
Secondly, it might be that the root stock has displaced the grafted variety, before or after you bought it.
Thirdly, Wyevale (like many other nurseries) offer a (lifetime) guarantee on plants they sell.
Fourthly, any sale to a consumer has to meet certain standards, including that it is what it is supposed to be.
Is this the first year it's fruited and obviously wasn't a Vicky P? Do you have your receipt?
Even if not, go and have a pleasant word with them - they may surprise you.