Clinton Netcare Hospital is awful with regards to making an appointment

Clinton netcare hospital needs to figure out their appointment system, I called them to make an appointment at the gynecologist to check up on my wife's pregnancy . On the phone, I was told that I don't need an appointment, as long as we are there between 13:00 and 16:00, on a first come first serve basis.

Today, I drove from fourways to Clinton hospital just to be told that they don't take walk ins, we need to have an appointment to see the gynecologist. Why was I told we can just come in when that wasn't the case?