Bad service from Avis with deposit refund

Avis rental Cape town airport is the worst, i rented a car on the 27-06-2025 and returned on the 2025-07-09, the lady that was assisting me with rental was friendly and explained the charges and insurance as well as the deposit fee. 2 weeks after the car was returned i received invoice of the amount due that i need to pay total of R3642.98. I sent email requesting in details what the fees are for because i paid for the insurance and other fees that were included initially when the car was booked, after a week i received email with fees that i was told that were covered with insurance that i paid. I was informed that i signed agreement acknowledging the waver fees of which the lady that was assisting me explained differently and now Avis is sending me sms of Legal Final Notice of the account that still reflects and i am not paying fees that were not disclosed to me. This is very bad service i will never rent a car from Avis again.