Would this be considered harassment?

In the lunchroom at work, there's a bulletin board to post ads on. We've never had to have ads approved. I hung up an ad for my scooter and my truck giving my phone number and saying people could come to the warehouse, where I work, to see me. At least half the people at work know me, so it's no problem to find me. Well, someone took my ad down. I thought, OK, maybe someone wanted one or the other and took the whole ad for my number. No calls on either, though. My second ad requested that they leave it up unless they bought both vehicles. I sold the truck and crossed it out of the ad. Then the ad disappeared. My third ad told people to grow a spine and come see me in person and leave my ad alone. Someone else's ad for a TV is never bothered. It's a UAW factory, and as far as I know, no UAW members have anything against me. My only real enemies are a couple of douchebag group leaders (management) who still tried to act buddy-buddy with me, probably just to put on a good show. Whoever it was, can it be considered harassment? That board is free for anybody to use. Except me.