But I have proof that I paid all the tolls for the remaining 27 out of 28 days of the rental period. So charging me a 'convenience fee' for days for which I clearly had paid the tolls using another method is inexcusable.

I could understand if I had no evidence that I paid tolls by any other method for the entire rental period, but that isn't the case.

I shouldn't be penalized $40 because of a transponder glitch. And Avis would not have paid a fine. In Florida, if someone 'runs a toll' they will first check the registration to see if the vehicle is equiped with a transponder, and they will only charge it with the correct toll (understanding that sometimes transponders go on the blink). They would never charge a fine on a vehicle that is properly equiped but misses a toll.

Susan