After the Jessica, 33, shared a photo with her new partner, Kai Carlton , Ruby commented on the pic.
"Congratulations, so happy for you both," she wrote.
However, Jess didn't take the comment as a compliment.
"@RubyRose I have requested you not contact me for over four months now," she began in a reply on Instagram. "You have been given my grace of being ignored on every other private platform, so the fact you continue to ignore this to contact me here publicly under the guise of wishing me well, is continued harassment."
Ruby was quick to reply, claiming she wasn't aware of Jess's claims
"That is news to me. Copy that. Good vibes only," she responded.
Ruby and Jess dated for about two years before splitting earlier this year.
Jess revealed last week that she is now in a relationship with Kai.