Selling a Trailer

My trailer is in a rather large trailer/mobile home park and there is currently only one other trailer for sale in here.  9 days ago I listed my trailer for sale with the park office...they'll receive $1000 commission if it sells.  So far I'm not sure they've even taken photos to put on their website and they haven't even bothered to put a "for sale" sign in front of the trailer.  

I went out yesterday and bought a "for sale" sign and put it in the front window.  I don't think I should have to do this myself, especially when the park receives such a huge commission regardless of the price of the trailer.  Mine is listed at $7,500 U.S. so it's on a much lower scale than any of the trailers that were on the website this past 9 days.  I wonder if my low price would drive down the high prices asked for the other trailers??

In any case, I don't believe they're earning their commission in regards to my little trailer.