A real estate agent is duty bound to present all written offers to the seller by the realtors code of ethics. It may make you feel better to file a complaint but it is not an easy process and in the end unless it is a repeat offense little will likely happen. That said I am a strong proponent of the work of all of the local professional standards committees and have served on mine throughout the years. Be sure to submit as much detail in your original complaint as possible.
If you buyer walked on a contingency (if they still had one left) their deposit is most likely off limits since they indeed walked away correctly. Ask your attorney to review the situation and get his/her opinion. Be sure to ask for the deposit in the mutual termination agreement (in most states you will need this in order to sell to someone else), make them say no, don't just give it to them. In MN they would have you over a barrel though since you need them to sign the cancelation more than you need their earnest money.
To file a complaint find out the name of the local board of realtors that you agent is a member of and call and ask to speak to someone about filing a grievance for an alleged violation of the realtors code of ethics. I hope that helps!!
Why would you fear reprisals? Realtors compete among themselves for the business. If anything, they may be knocking on your door as soon as you cancel your agreement with your currnet realtor.
Please remember, you are the client. The realtor is your service provider. He works for you. If you are unhappy with his service, you can:
1) communicate your dissatisfaction to your realtor by giving him this feedback;
2) give advance notice that you expect to be apprised immediately when there is an offer;
3) review your contract. Know your rights and obligations and see if you can back out of your agreement with the listing agent and under what circumstances;
4) terminate his service if you are still dissatisfied even after telling him what your expectations are.
A couple of other thoughts, it is common in the area of MA where I practice for the expiration date on the offer to be seen as more of a goal than a specific technical deadline. If both parties are happy with the terms presented, and we are moving along, then it is not usually seen by either party as a crisis if the offer is not signed by the expiration date. Of course, the date and time of expiration can become critical in multiple offer situations, but it doesn't sound like that is what you were dealing with. Also, it is unusual, again, in my experience, to have an offer reviewed by attorney's for either side before being signed. The offer usually used is the boiler plate, fill in the blanks variety which doesn't leave us lay people too much room for legal wrangling. We usually leave that to the drafting of the Purchase and Sale contract, which the attorneys for both sides are very involved in. Was there something specific in this offer which was making you nervous? If not, and you just are the kind of folks who like to have your t's crossed and i's dotted - then I would recommend reviewing the offer forms used in your area with your attorney, before any new offers arrive. This way, when the next offer comes in, you will be comfortable with the terms and will be able to act quickly.
Again, I don't think we have enough information to lay blame at either the brokers actions or at yours. Look at the positives of the situation instead - she(or he) brought you a buyer, willing to make an offer which was in the right ballpark. So pricing and the marketing plan are not a problem. I would hang in there a little longer, be clear that you were disappointed with the way this played out, and with what steps you will both take to avoid this in the future. Have faith that for whatever reason, this was not meant to be and there is a better buyer out there for you. Best Wishes, Stacey