Grimes Says Elon Musk Won't Respond to Messages About Child's Medical Crisis

Grimes is taking to Elon Musk's social media platform to try to get in touch with her ex ... publicly revealing one of their kids needs urgent medical help -- but, Elon won't call her back.

The singer-songwriter posted on X Thursday afternoon in a desperate attempt to get the attention of the platform's executive chairman ... asking him to please respond to her to discuss their child's medical crisis.

Grimes writes, "I am sorry to do this publicly but it is no longer acceptable to ignore this situation. This requires immediate attention. If you don't want to talk to me can you please designate or hire someone who can so that we can move forward on solving this. This is urgent, Elon."

When pressed for details, Grimes said she won't divulge anything else on X ... but, added she needs to get in touch with him to save their child from "life long impairment." She said if she needs to apply public pressure to get a callback, so be it.

Worth noting ... Grimes and Musk have three children together, sharing son X Æ A-Xii -- who recently made an appearance at the White House -- daughter Exa Dark Sideræl  and son Techno Mechanicus. It's not clear which child Grimes' post is referring to.

We've reached out to Grimes and Elon -- who dated on and off from 2018 to 2022 -- about this alleged medical crisis ... so far, no word back.

Of course, Grimes isn't the only woman who has recently turned to X to try to get EM's attention. Just last week, Ashley St. Clair -- a frequent Fox News guest -- posted on X to ask Elon to call her to discuss their own child ... claiming she gave birth five months ago, and Elon's ghosted her in the aftermath.

Musk publicly questioned the paternity of the child ... though he didn't hash anything out with ASC online. Unclear if he's reached out in private.