Help! Buyer Pulled Out At Last Minute and Now Demanding Double Deposit Back From Us

Please help us -We are British Citizens with a property in Spain - A couple of months' ago we sold our property to a Spanish Citizen who pulled out at the last moment because he says our estate agent/lawyer witheld information about the legalities of our property. We have email evidence from our agent/lawyers confirming that the buyer went to the Town Hall and was made very well aware of the legal situation. Under Spanish law we kept the deposit from the buyer. The buyer is now suing us in the Spanish Courts for DOUBLE his deposit back, 46,000 Euros plus his legal costs. Do we have a case to fight him in court? We just cannot afford to give him double the deposit back. By the way we did offer him his full deposit back at the time but he wasn't interested. I would really welcome any advice please ASAP as on Friday there is a case in court to put an Emargo on our property!