North Texas Tollway Authority NTTA PAY FOR NOT USING TOLL ROAD Plano, Texas

I have a tolltag acount with TxTAG for 4 years. NTTA recently began mailing me zipcash invoices for tolls I did not use.  The supervisor says over the phone and by email that they are legitimate tolls and there is no "double-billing". After many conversations with the supervisor, she refused to remove these charges.  Many of  the charges are $1.17 for one location.  On one occasion the invoice shows a charge for $5.85 for the same location. There is even a charge from toll use one year ago. This one shows on my TxTAG acount and has been paid.  NTTA will not remove these charges.  They said they will reduce them to the discounted rate if I purchase tolltags from them.