Had the same issue with a hood scoop a couple years back. Good price, got tracking #, it never arrived. After two weeks called them, got the same story as you, out of stock. I checked their stock, still had four but at a significantly higher price.
Obviously they were out of stock at my price point.
They asked me for a rating, I gave it, they would not publish it.
I could gripe my **** off about it but I find them as still one of the better places to shop so I just sucked it up and bought one from Summit. Interestingly, the one from Summit was the exact one I had ordered and it was on sale for the same price Amazon cancelled my delivery on.