Problems with E- tolls

I am not happy with the service I received SANRAL staff over the weekend. I was travelling to Venda during the past weekend and decided to load R600 on my e- tag to allow me to go and come back with no problems. At ALL of the e- tolls I stopped at my e-tag was not working and the staff was not helpful at all. I had to pay extra money which I did not have in order to get through but according to me it was not my problem that their tags do not work. Only on Monday when I returned was I told that the battery on my tag was flat and was issued another tag. This is unacceptable, I don't understand why I have to pay more when the tag not working is not my fault. Here I am using tags that most people in SA are against and quite frankly I would not recommend the e- tag system to anyone. Very disappointed in the e- toll staff on the N1 from Pretoria to Venda, their lack of assistance spoke volume of how they viewed me as a customer