If there is a valid contract, you are welcome to legally push it through. Whether one wants that? I don't know. Otherwise, I can plan a lot. Whether the budget fits in the end is debatable.
Visible on the drawing, confirmed by email (photos/example images included).
Email: From whom to whom? Who confirmed what there?
Now the construction company says: That costs us too much!
Does the construction company say it costs them too much? Does the construction company say it will cost you too much? Do you say it is too expensive for you?
And regarding the headline: is there a planning misunderstanding? If something is too expensive, then it is not a misunderstanding.
And regarding the headline: is there a planning misunderstanding? If something is too expensive, then it is not a misunderstanding.
Then it is also not a misunderstanding, but a mistake. By the way, legal transactions can be contested due to a mistake - there was still the legal question...