Realtor had two parties under contract to purchase a property

[Benjamin Prescott]

I am looking for any recommendations for any lawyers in Maine that may be able to help with a legal issue regarding a contract dispute I am currently having. 

Last November my partner and I put an offer on a short sale property. We were told that there was currently an offer on the property but were still accepting additional offers. We signed our P&S and the backup addendum and submitted. We were told by our realtor the next day that our offer was accepted and we were bumped to first position. Being a short sale we still had to wait for the bank to go through their processes and appraisals so we knew it would be a few months before any further movement in the process. during that time our realtor reached out to the seller agent on the status and was given updates as they came. In March we were told that the bank had accepted the offer and the closing was to be scheduled. At this point the seller agent informed our agent that we were not getting the property because we were still the backup offer. Upon further investigation it was revealed that the estate attorney for the property mistakenly signed the backup addendum in the section that released that contract making us the primary offer. They essentially told us "too bad" and went ahead with the closing with the other party.

Our questions are how much of a case do we have and what kind of compensation/cost to fight this? We have also filed a complaint with the state Real Estate Commission but they have yet to make a ruling (and they have no real timetable as to when they will get to it). 

Thank you in advance to any recommendations/referrals!