Zillow Misleading promises on promoting my nationwwide Internet

I am a real estate agent and was looing for ways to grow my business.  I got a call from a Zillow rep and the went over their plan to send me leads.  They said I could buy impressions/page hits on listings from my area.  I spent around $500 for a few months of leads.  They didn't tell me that they were selling the same impressions to other agents and my name would be poppoing up with several other agents.  When I complained she said, "I should have known that."  Not sure how I should have known that when I was told I was buying the impression.  I just want to keep other people from making the same mistake and throwing their money away.  It has been a complete waste of money.