And honestly expecting the receptionist/check in person to have any idea of what will be billed is not something most normal people would expect. This is not a restaurant with a menu.
Other countries do things differently, have higher taxes, less people, etc. Sorry that you made an assumption. I remember taking my daughter to an urgent care years ago and asking if they took x insurance carrier. They stated they did. But what I didn't ask and what was not mentioned was that x insurance carrier was OUT of network and would pay much less. So it is sad that you have to learn to ask more than one basic question.
And I suggest seeking out a local doctor that you can see who is going to be a better choice than the ER.....