Illinois I-Pass Getipass PAID DOUBLE FOR TOLL FEES-TOLL BOOTHS DIDN'T PICK UP TOLL FEES! 294 north, Illinois

In the month of October My husband used the toll road to go back and forth to work. He started his job in July, he used tolls 41-163rd st LN 63. 2n and39-83rd st Ln54, 35-Cermak Rd Ln 53 or 62 on the !9th of January that evening. Unfortnately, he used the transponder that morning as well and no toll fees were taken out of my balance. The same thing occured from the beginning of July to October ultimately resulting in a toll violation letter being sent to me stating I owed Illinois toll fees in the amount of over $6000.00.
I immediately called a representative in October to dispute the fees she and several other Representatives and supervisor told me that there was no way to dispute, that I owed the fees. Every time I checked my online account the balance would say ($.45) so I believe that I didn't owe any back fees. I totalled the transactions for his week and added $25.00 dollars a week for my husbands weekly commute. I tried explaining this to several representatives, supervisor they insisted I had to pay $1.50 for some transactions and $ 21.50 for the earlier missed tolls.

I told them how long I'd had my ipass which was around 9 years and never had this problem any tolls I missed  I just added the toll fees initally charged and paid them in full. Never any violation charges to this magnitude. I ultimately paid over $700 dollars for toll fees. Is this legal? how can I dispute this to a different department than someone that already works for the Illinois toll way? I mean they have to do their job so naturally they can't go against the rules that getipass has already set in place?