Cannot find app in store, but registered in website search.

While visiting family, my sibling showed me the Taiwan Carrefour app on his iphone which was downloaded from the app store. Subsequently, I searched the store and found it non-existing but could find it on the app search and the carrefour store website via QR code. Scanning the QR code with the iphone it took me to the app store then registered your request cannot be completed.

Does this happen often?

Please help.