How to handle multibyte string with accents as heading?

[nocodelab]

Hello guys,
I'm struggling to handle a CSV file with multibyte string with accents in the heading.

Numero,Denominazione,Categoria,EANCode,Numero Produttore,Denominazione Produttore,Prezzo,Quantità disponibile,in_arriva
This is the heading, and as you can see, one column is "Quantità disponibile".
When I try to access that key in the $row array I get "Undefined array key" error.
I believe I can handle it with formatHeaderUsing() but I can't find a way to remove that "à". Obviously I have tried with str_replace :P