You will probably want to get your real estate broker involved or hire a real estate attorney to look at your timeline and correspondence. That is assuming you still want the house.
If you don't want it, then you can sign the release and get your earnest money back.
If the sellers have a done deal, I would think they'd move forward unless they have other offers on the table. However, your phrase "seller has listed the property in the contract period" confuses me. Was it previously a for sale by owner, or are you saying that the property remained listed on the MLS while under contract? If the latter, property do stay listed on he MLS, but their status changes from Active to Active-Option to Pending to Sold depending upon the progress of the contract towards closing of escrow.
Unfortunately, it seems your first mistake was asking BoA to rush to closing. Lenders are extra cautious about making good loans these days. It takes as long as it takes to get it through underwriting. Loan originators and realtors don't like to use up their hard earned brownie points to push the loan through unless there is a compelling reason to do so.
I does sound like you and the seller were operating without the assistance of a Realtor. You do have the assistance of the Title company but they can not advise one against he other. You need to go to a Real Estate atty.. You probably did not use the contract Cindie is referring to if you did this on your own as that contract is not for non agents.
I would really question if this house is a good purchase with the difference of opinion on the appraisal. If you don't have a buyers rep I would get one now. The seller seems to have learned that they need representation, but I bet you are a named exclusion on their contract as to their paying the listing agent if you purchase.
If you have a Realtor they should be able to get this fixed for you? If not then honestly you have bigger problems and with out getting an Attorney to help you honestly.
Sorry this is happening to you and the pieces don't seem to fit correctly.