Checkers sixty60 service

So, I am having an issue with options on the app. I was looking for briquettes. So i was looking for one. Scrolling through the app, i came across the bush baby 2 for R80. So I opted for that, as it is a good special. Nowhere on the app it showed out of stock. I chose an alternative. But by doing that i would want the option to change the quantity then cause now its no longer a special.

Now the add 2 as the quantity on the special was 2 but i now end up paying almost R40 more.

Not fair towards consumer. I know it pops up that its not part of the special, but give me the option then to change my quantity for the alternative.

Regards