And then, of course, you go back to CL and flag their post, right? ...You do report abuse on this free platform so that everyone's experience can be improved, right?
Other than "getting your account banned for multiple reports on multiple postings"? Nothing. If you see someone abusing CL, you report it. If you don't, you're just helping make sure people can keep being dishonest on the platform.
Whenever I'm buying something on CL, like say a car, I always ask the person who answers the phone: "I'm calling about the car. Tell me X about it."
If they reply "Which car?" then you've reached a dealer, not an owner.