All real estate transactions are contractual so as long as the agreement is in writing, really short of a few set expenses, everything else is up to the negotiating parties.  So in essence, your seller had the bank agree to short sell the property to the buyer.  Usually the short sale negotiator is hired by the seller.  Further, ensure a short sale negotiator is not required to be licensed in your state separate and apart from the real estate license, check with your state's consumer protection bureau.  If the buyer agreed to pay for the short sale expenses, then there is nothing that can be done.  If the seller indicated this particular buyer was to pay for it and the buyer decided not to, the seller can choose to not sell to the buyer.  There doesn't appear to be any wrongdoing on the broker's or realtor's part concerning these expenses.