Back to OP's original question: Unless your posting was a prohibited item, or against a CL rule, a sufficient level of flagging from multiple users will get your post removed. I don't know what that level is, but I'd guess 3 or more.

Usually you see it with competitive sellers and businesses trying to keep others from posting stuff, or if you have someone who wants your item on the cheap, or someone you ticked off. I've seen it many times.

Wait a few days and list it again with some changes to see if the guy who's flagging it gives up on messing with you.