Going into reverse with Avis over getting a hire car repair receipt

We had an accident. But our insurance company won’t meet our claim without oneIn September we hired a car from Avis in Perugia, Italy, but we reversed the car into a water hydrant in the hotel car park causing some damage. We were advised by Avis at the airport that we would receive an email to inform us of the cost of a repair prior to any money being deducted from my husband’s credit card. We had taken out extra insurance in the UK to cover the excess after reading an article in th