avis cars etag issue

I rented a car at King Shaka on Tuesday 26th March, I left the airport and was on my way to Balito, I had to pass Tongart plaza, well that should not be a problem the avis cars all have E-tags, I selected the quick etag lane and to my shock I had to reverse out of the lane and then join a long queue, This has happened on many occasions now when renting avis cars and now I have had enough of been embarrassment at toll gates, avis if you have a tag in the car make SURE IT WORKS!!!!!!!