Unfortunately, I had to cancel my booking in the 48 hours period before pick-up. Since my rental period was 2 days only, I got no refund at all, because in this case the cost of a 3 days rental is subtracted to the amount I had paid (2 days).
To find this clause in their terms of service, you really need to delve into their website very deeply (i. E. it is something that they will not tell you in the moment you book).
Please, stay away!