Invalid refueling charge

I was charged R238 for 16.11L of Petrol, after I had refueled the vehicle before returning it. I presented this to customer service with proof of the R420 (29L) I spent refueling after driving 550km on freeways in a Sandero 900T dynamique with a mixed cycle consumption of 5.4L.100km.... The sums just don't add up. Upon presenting this to Europcar, they concluded that they would refund a portion of the money.... After a significant time spent stating my case via email I am told (by Thuba Nkomo quoting incorrect facts) in response to my email, that "some of it is not accurate". She then continues to quote, incorrect, counter facts. This is borderline **********.