buyers back out at last minute

calif.1 week before the escrow closed the appraisal on
our house came in 15,ooo below and immediately their broker
and our agent requested another one,because they knew it was
not correct.The buyers went out the next day and bought another house without waiting for the new one,we in turn had
purchased a brand new house and had put out 3200 for the upgrades and deposit.where do we stand legally,can we take them to small claims court for the money we spent on the repairs they requested for closing and the money we are out of on the new house we cannot purchase now.

[HomeGuru]

Confusing post.