Got charged extra for giving the car back early

<p>Hi. I hired and paid for a car, for 9 days. This meant that I had 1800km free. However, I gave the car back after 8 days, so I got charged an extra R500. They said if I gave it back the next day I wouldn't have been charged. That make no sense at all. I paid for 9 days, so why must you recalculate because i gave the car back early.</p> <p>Ref ********** 9ZA0</p>