Probably worth at least one shirty "This is what you advertised & I paid for it at the price you asked...." email & see what they come back with. They should honour the orders placed at that price & cop it on the chin as their own mistake.
Their SKU codes have had their warehousing people despatch the wrong product. It's an internal fuck-up.
Sure, they'll feel sheepish about their own stuff-up & have obviously already realised their mistake, but that's not the customer's fault.
Offer to return the incorrectly-delivered product at their cost, so that you can get what you thought you were actually ordering. Polite, but insistent.
Nothing ventured, nothing gained.......