What sort of contingency are you talking about?? Contingent upon private home inspection? Then you decided not to have it inspected.. no not a breach. Contingent upon selling your home, and your home has not sold.. then that is not a breach. That is the reason you have a contingency in a contract, in case you cannot preform. It does not breach the contract it deems it null and void. Something else??? be more specific and maybe we can help.
Not knowing all the facts, nor what the contract specifically states--your agent is your best source of information--or consult with an attorney who specializes in real estate, have all related documentation reviewed, and then make a determination. Generally if the contract is not fulfilled it would be a breach.