Dear Sitifan,
No native speaker would ever say these sentences. An ordinary way would be :
e.g. "We're both wrong."
You could add emphasis by saying (in speech):
e.g. "It wasn't just you who got it wrong - I did too".
It is common to see "not only .... but also" constructions in complex and formal, written sentences.
e.g. "Not only did he fail