Sorry for your problem but your contract was with the former owners and from what you say they will no longer have a villa available to rent. The new owner has decided not to rent out the villa and is under no obligation to rent out the villa unless it was specifically required under the purchase contract (I am guessing it was not).

Your only recourse is to get a refund of the rental you've paid in advance.

Unless you specifically have it in writing neither the former owner or the new buyer is obligated to pay any additional costs you might incur renting a different villa.