Is this Realtor unethical?

[Thomas Tarry]

I'm an Associate Broker in Syracuse, NY and this happened to me last week: I submitted and offer for a condominium on behalf of an LLC. The agent called me back and countered. My buyers accepted and we signed the deal. He asked me for the LLC paperwork listing the LLC members. I sent it to him and he sent me the signed contract. Two days later I get an e-mail from the sellers attorney disapproving of the deal (the seller and attorney are related). I call the agent for an explanation and get no response. Neither did my clients attorney when he called the sellers attorney. The natural thought here is they got a higher offer. Problem is the unit is still active. I write up a new, all cash offer and submit it. I get no response from the agent. After 24 hours I call him. He doesn't answer but texts me he's on a listing appointment, couldn't take my call and informs me the attorney was supposed to send everyone a letter. Ten minutes later I get an email from the sellers attorney stating he disapproves the cash offer. My client informs me he had an unpleasant interaction with this agent recently (my client owns a local fence company). I believe this agent violated the code of ethics when he didn't present my offer "objectively" as required in the Realtor code of ethics. This home is still active on the MLS. Should I file a grievance against this agent with my local board?