If you wrote an offer on a short sale, the seller would have accepted the offer subject to the bank's approval. You can request that the listing agent provide something in writing stating that the bank did not accept your offer. Most short sale negotiations are conducted through the Internet, telephone and via fax. Sometimes there is a way to provide documentation, other times there will not be documentation if the bank straight out rejected the offer. At minimum, the listing agent could write a letter and have the seller sign it stating that the bank rejected your offer. Was your offer at market price or below market price?