Did you know that in 90% of cases where the badge does not work, it is because it has been incorrectly positioned on the windscreen? The way the badge is fitted is very important to ensure correct transmission between the badge and the free-flow toll gantry. If the Télépéage badge is correctly attached to the windscreen, there will be no billing anomaly. 

Your badge must be attached to the windscreen next to your rear-view mirror for it to be detected. If your vehicle has an athermic windscreen, the bracket must be fitted in the dotted area next to the central rear-view mirror. If in doubt, consult your vehicle manufacturer's manual. 

Take a look at the images in the tutorial: https://www.fulli.com/actu/comment-installer-son-badge-telepeage