The question at the end of the day is whether there was a signed real estate agreement between the parties.  If not, then there is not liability on the seller.  If however, there is a signed agreement and the buyer put down money and secured financing and then the seller pulled out, the buyer could enforce the contract under what is called specific performance.  This is a doctrine that allows a buyer to force the seller to give them the property based on their deal.  It prevents what you are describing from happening.  I would need to see the contract in order to give you a definitive answer.