Agent scammed us at the auction

[Basu G.]

We have had many people laugh at us when we told about this. 

We had an agent who would send us some properties he thought were good buys from listings on FMLS. He accompanied us to the auction on 11/07. At the auction he said he has registered as a sellers agent and would charge us 5% commission.  This should tell us we are novice folks and trust people easy. Any how we didn't buy anything from the list of properties that were from auction.com. We ended up purchasing a property from one of the other callers and I called the numbers and we got ahead in the bid. We gave this dude 5K (2K cash + 3K check) as he said he worked all these days and hasn't made any money and he could really use it and we could treat this as commission.  We learnt yesterday evening that the property we got was reinstated and it is an invalid sale.  I told him to return the money back and we blocked the check.  He isn't ready to give the 2K back. What should be the recourse? We want to file a suit against the agent..