You should call Nat's Broker at 577-0001. Her name is Nancy. Go to the source, rather than random agents on the internet. The listing shows that it is under contract to sell as of Aug 20 of 2012. Is this contact null and void by now? If you can't get Nat to withdraw it, then Nancy can certainly look over the contracts and the history, and determine what the real status is for you.
What type of contract did you have? An agency contract that reflects agent/client representation? and if so, was agent representing you to buy or to sell? This will help determine what type of form is needed as different forms can officially dissolve different contracts. Ie: release of contract, release of listing agreement .