Not refunding security deposit due to breach of oral agreement.

I am a lawyer in CT and practice in this area of the law.  A contract is enforceable where there is a meeting of the minds on clear and definite terms.  In this case you had an agreement as tot he secruity deposit.  if the buyer failed to return the car within the set time period then you may keep the deposit.  the court should rule that you are entitled to the deposit.  i imagine that the buyer has returned the car; correct?  I do not think you have a counterclaim for the car unless you can prove that you gave the deal to the buyer while the buyer knew that you had a better deal and gave something up to give him the deal you did.  i doubt the judge in court will permit you collect these damages but you can certianly make a good argument.  small claims court favors the consumer, which is why you want to avoid looking like you are now trying to take advantage of this buyer.