Thats odd, they show it on their website, I can have it local to my home store by 9am!!!! Take a look, can you see it online, can you have delivered to your home store?
Eitherway I would call back and ask for the guy who helped you. Then ask why its on your website but you cannot source it??? If he does give you an amazing answer its time to move up a level. Ask for the manager on duty, guessing he can will figure it out for you. If not order online for store delivery. But who knows maybe in your area there is some reason they cannot. (But I doubt that.)
I find calling retailers (Clothing, home improvement, outdoors, auto parts, plumbing, housewares, etc.) of any kind for help drops your odds of success by 70%. (Unless you give them a part number and they know how to do a inventory check.)
I have often found I call to ask do you have XYZ in stock? I get hold please, then sorry we do not have that in stock. Then I hang up but question if they even looked (Not looking is more common than you think.), did not know what to look for, did not know where in the store to look for it, or looked but missed it. (Did not see it, was put back in the wrong place, etc.) So if there is time I go look anyways, often I show up and whamoo its right there in stock!