English Experts

[João Souza]

You got me all wrong.

Acabei de ouvir no filme "Caçadores de Mentes".

[donay mendonça]

Olá João,

Também,

You´re quite mistaken.

[pondedaniel]

How are you Joao?

plus

you're dead wrong

Take care,

Teacher Pondé

[hesleioliveira]

Olá João!

Mais uma sugestão:

(Way) off-base : "redondamente" enganado. Veja: http://idioms.thefreedictionary.com/off+base

Bons estudos!

[Henry Cunha]

You got me all wrong.

Acabei de ouvir no filme "Caçadores de Mentes".

Let´s not forget the "me" in the expression. So possibly

"You don´t really know who I am."
"You misunderstand what I am doing here."
Etc.

Regards

[Eric]

You are sadly mistaken!!!( voce esta redondamente enganado )
seeya mate

[maryziller]

How about

You're totally wrong for me. = We are not a good fit as a couple, we are not compatible.
You are totally wrong about me. = You misjudged the person.
You're totally wrong = you are not right at all, not even a little right; you are totally mistaken
That is totally wrong = that is morally wrong to do, e.g. childhood labor or exploitation

You can get something totally wrong, meaning that you misunderstood.

All of the other suggestions also sounded valid to me.

[pondedaniel]

also

you are Flat-out-wrong

Take care,

Teacher Pondé

[Adriano Japan]

*Adding:

be sorely mistaken

→Example:
If Ferris thinks he can coast through to graduation, he is sorely mistaken.

FONTE: from a line of this film.

[Otaviano Neto]

It is also possible to say "You got it all upside down".