It's clear they don't want to sell you the item at the lower price, and they can't be forced to do so when they're offering you a refund. It depends on whether your jurisdiction has any funky laws on the matter, but often the company has the right to cancel your order after it's been placed (can always say the inventory in the computer was wrong, there really weren't any in stock etc.), and providing a full refund for shipping you the wrong product amounts to the same thing as a full refund.
It seems I am talking to my self here. But that doesn't matter as my experience might help others. I received the first 29" Samsonite 11 Hardside Spinner from the rogue seller. Negative feedback and my stand that a binding contract existed between me and the seller. Whether I accept a refund is up to my discretion. I can insist on performance of the contract. That's what I did. But I do appreciate you and others taking the time to respond to the OP.