Fuel Bill Dispute - TKSIA***RA6

I recently travelled to Durban and hired a car (Hyndai i10) from Tempest. On my return, I personally & physically filled the vehicle at the Sasol garage, just a few metres away from the Return/Drop-off zone. I travelled approximately 277 kms and filled R187,93 fuel. A week later I got a bill for R108,60 from Tempest stating the tank was not full. I cannot comprehend how such a small vehicle would use R296,53 for a mere 277 kms. I feel \ripped-off"and worst"