Farrah Abraham -- Fake James Deen Threatened Me!

Farrah Abraham had another creepy encounter with James Deen ... but it had nothing to do with porno sex -- or even the real James Deen.

The sex-tape Teen Mom received an email Monday from someone posing as the porn star ... and threatening to call Child Protective Services on her ... apparently for bringing her daughter to her negotiation with Vivid Entertainment, as TMZ first reported.

"Yup definitely calling CPS ... have fun with driving and filming your daughter at the same time and bringing her to Vivid entertainment. You fail at life," said the message obtained by TMZ ... which came from an email address that includes Deen's full name.

Says Deen: WASN'T ME!

"Personally I would like to apologize to Farrah on behalf of whoever sent this email and let her know that I am on her side and will happily verify that her child was not exposed to any adult content during the duration of this shoot," Deen wrote us.

He adds: "Also… Not cool people!!!!! Leave the girl alone!!!!!”"