Poor follow through and unprofessional

I recently put an offer in on a property that Ms. McWilliams was listing. I was very unhappy with Ms. McWilliams level of professionalism. She promised to get back to my agent with an answer from the seller by noon. We heard nothing. We were then promised an answer by the end of the business day. Again, we heard nothing. When my agent's phone call was finally answered by Ms. McWilliams, she said her client did not want her to respond to our offer, even though he had already accepted another offer in the meantime. A courteous and professional realtor responds to a legitimate offer, even if the offer is not accepted and ESPECIALLY when explicit promises are made to respond at a particular time. I find her behavior very unprofessional and would not advise anyone to do business with Ms. McWilliams.