Magarithea thank you for trying to explain but I think I do understand.
OP told us that she wanted her booster because she was going away and going to a concert. Now I don't know whether she is eligible or not because this thread is full of discussions about what "six months" means. But I do know that she hadn't been called for her booster, but tried to book one anyway, which some people have obviously been able to do, and got a bit annoyed with the person on the phone who wouldn't do what she wanted her to do. Probably because she was not allowed to do that. Because the system wouldn't let her. So no point at all in complaining about the person on the phone, or the system, or anything else.
We've got an almost-miraculous set of vaccines, we're mostly on our third dose while many people have none, and so I'm afraid I do get a bit tetchy with people who complain that they are not getting exactly what they want, when they want it, in the location of their choice, and there has been a lot of that on this thread.