Car Hire Company Cancelling a Pre-Paid Booking for July

Mosschop71

I pre-booked and paid for car hire last year for our summer holiday in Italy this year. The booking was with Hertz via Rentalcar.com and Rentalcar have just emailed to say the car will not be available and have offered either to swap the booking to another provider( same car and price), Nolegiare or to refund me. A refund is out of the question as car hire prices have gone through the roof and I would pay almost double to go elsewhere and I chose Hertz because I have a good history with them. Added to that, the alternative provider doesn't even have a presence in the terminal we fly into.

I have already gone back saying this isn't satisfactory and have asked them to provided me with an alternative suitable car from Hertz but in the event that they won't play ball what are my rights?

Thanks in advance.