Stating categorical disagreement (заявляем о категорическом разногласии)

That’s not true.
That’s not right.
You’ve got that wrong.
You’ve got it all wrong.
Wrong!
You missed the boat. (idiomatic)
You’re missing the boat. (idiomatic)
Wrong on both counts.
You’re wrong.
You’re dead wrong.
You’re off.
You’re way offbase.