Incorrectly charged for E-Tolls

My Avis experience is a nightmare I want to share. I returned my insurance hired car back to Avis on the 06 November and I was told my deposit will be refunded 7-14 days thereafter. On Monday 10 November I received an invoice from Avis which states I owe E-toll fees of R4245.99. they deducted my R2000 deposit and stated that I owe them R2245.99. I requested the E-toll statement on Monday. I received and E-toll statement on Wednesday afternoon 12 Nov. The statement indicated toll gates used on the N4. I informed Avis on 13 November that I did not travel on the N4 and that I dispute the charge. I asked them to look at the Cars tracker record which will show I did not travel to Mpumalanga. I also suggested they look at the E-toll tag because I suspect the tag might be in another car. I have had no feedback as yet. This means I am short of R4245.99 at no fault of my own. This is the sloppiest service I have had to experience with Avis and I escalated this matter up with my insurance. I would like to get my money back. My rental invoice is E***.