Jon, on this subject you are most likely to get as many conflicting opinions as there are people on the forum.
Print out a complete set of pages of the threaded email (both times), take them to see your lawyer and let him/her advise you. I doubt that a good lawyer will charge you thousands to file a simple case to enforce the contract or recover damages.
I have bought many properties, both physical and virtual and most of the time everyone honors the email communications of an offer / acceptance. Some courts consider electronic communications (email) the same as a letter / contract through the post office, others will not.