Diddy was apparently about to ghost his then-girlfriend if she didn't "get back on her "job" ... calling her out in an annoyed voice message played for the jury in his federal sex trafficking and racketeering trial in NYC Friday.

"Jane" -- Diddy's ex who is testifying under a pseudonym -- was back on the stand for a second day of direct examination Friday ... and, prosecutors introduced several voice messages they say the mogul sent to her. Play video content

One voice message begins with Diddy telling Jane he's about to up and disappear on her ... because she might be giving him the silent treatment, but he isn't going to play games with her.

Diddy goes out of his way to say he's not threatening Jane ... saying he's too old for her BS -- and adding it's alright for them to fight, bu

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