Sixt Car Rental Sweden Prepayment Cancellation Refund Complaint

I just made a car rental reservation through Sixt's Swedish office. Unfortunately, I had to cancel the reservation well in advance of the scheduled rental date due to unexpected circumstances. When I tried to cancel using their mobile app, I was disappointed to learn that they would only refund half of the rental amount. It felt like I was being penalized for canceling ahead of time. I believe this policy is unjust and irrational, particularly given the ample notice I gave.