conspiracy theories aside, you're probably getting insta-flaged by the system.
I'd start with posting your ad here for help:
https://www.craigslist.org/about/hel...ity_moderation
I've sold tons of cars and motorcycles on CL, and I remember on one ad, I was getting auto-deleted minutes after it went up. Not sure why. Turns out it was because my pictures were too big, and CL system auto-flagged me.