Yes, most hotel bookings are fully refundable provided that you cancel prior to the accommodation's cancellation deadline, which often is within 24-48 hours of your arrival date. If you booked a non-refundable reservation, it may still be possible to cancel it and be given a refund within 24 hours of booking. Plug in your dates, click on "Search", then you can filter by "fully refundable" to review the best deals near Mount Aconcagua.