Why do baristas disregard the toppings?

I always order on the app, and always have some sort of topping (brown buttery, caramel crunch, cookie crumble, etc.) that I add under customization. 75% of the time when I get to the window the topping is not on the drink and I have to ask for it. Then today this happened and I asked where it was and they said "oh we no longer have that topping", but why not ask at the speaker "is there another topping you would like?" Why do they just disregard the topping completely? Yes, its only 50 cents, but its MY 50 cents, and I don't feel it should be donated to Starbucks at the baristas whim. Just my rant.