I would really like to have more information with your question. However, even with more information, I would advise any person asking about the validity or whether a contract is binding, seek the advise of an attorney. An attorney can advise you, assist you, and help you enforce the legal rights you may have, if in fact, your contact is found to be binding.
Kay Pearson, CRS
Max Broock Realtors
31 S. Main STreet
Clarkston, Michigan 48346
In Michigan, if there are no changes to the counter and the buyer signs, once the sellers agent is notified and recieved a copy, it is binding. There is a place on MAR forms for the seller to "bottom line" or acknowledge the buyers acceptance.