Unfair Service offered by Insurances- Paying tyres and Windscreens at Avis

I have Insurance for Motor and house hold with Momentum Insure and on my cover i have vehicle tyres and windscreen insure individually, and also included a curtesy car during the absence/repairs of my vehicle. i have an accident / incident and the car repairs has been authorized ( claim number CP939219MP ) and the challenge was when i was supposed to collect a curtesy car (Avis), Avis is charging me a deposit which i am willing to pay because i will bring back the car fuel the same as i received it, the challenge is that Avis want me to buy Tyre and Windscreen insurance with the @ +-R59 per day, my challenge is i went to Avis to collect a curtesy car not to offer the a business ( Buy something ) and i will also not take a risk to drive a car without these mentioned items covers since, we all know that spikes issues and the condition of our roads in South Africa, I have them insured them on my personal car with Momentum now why should cover these items twice. Solution: - 1. Ask Avis to waiver these cover. 2. Allow me to pay less of these cover on my next premium. 3. lastly allow Avis to include this cover on the deposit ( if none of these covered items are damaged i must get my money back) Thank you.