Hi bjen

Spanish law does not indicate that you have to refund double the amount, this is agreed between the parties in a private purchase contract. In fact, it may be possible that the buyer enforces completion of the transaction in which case they could get a ruling from a Court forcing you to complete.

I suggest that you advise your solicitor that you don’t wish to complete and that you will only return the 15k. Your buyers may just take the money and go away.

Regards