The film follows a young Polish woman who is imprisoned by a Sicilian man.
"This should not be anyone's idea of entertainment, nor should it be described as such," said Duffy, who recently revealed she was held captive and raped a decade ago.
Netflix said it would not remove the film, which it said carried warnings.
Adapted from a novel by Polish writer Blanka Lipińska, 365 Days was not produced by Netflix, but was picked up by the streaming service in June after a theatrical run in the UK and Poland in February.