but if I were you, I would rather believe them. The reason is that if they dare to fake the evidence, they are taking a huge risk that you are going to sue them. By that time, I am sure others would be doing the analysis on your gas tank instead of them. Anyhow, it's just 11 bucks. I would rather think that they really thought you were the guy who were suppose to pay the money and they were not interested in prove you "stole" the fuel but get the money back.