Burger King - has supply issues and never has stock of items

It is interesting that Burger King SA has vegetarian options on their menu but whenever I go to my local branch 8 times out of 10 they don't have that option. What is their response - "Supply issues". Really??? why even advertise these options if they never have them in stock. I can't eat anything else as I am a vegetarian. So I no longer go to save myself time and the frustration of hearing the same response every time!!!!