According to the docs, Prokop -- an actor who once appeared on "Modern Family" -- pinned Hyland against a car during an argument about her outfit back in May and unleashed hell ... calling her "cunt, cunt, cunt" and choking her.

Hyland says in the docs, "His grip was so tight that I could not breathe or speak. I was scared and in fear for my life."

Hyland says Prokop entered a rehab facility in August -- but he got out on Sept. 21st ... and claims the director of the facility contacted her and told her it would be in her best interest to get a restraining order against him due to his mental state and attitude against her.