Overcharged, then harassed and completely inconvenienced

Terrible experience recently with a rental where I was made to travel 3 times into a branch to make a payment for which I had requested but did not receive an itemised invoice. On my third trip, I used my card to swipe for the invoice balance, was given a receipt and a confirmation of payment. since then, Avis staff has called and near harassed myself and my mother for an error on their part, claiming that the amount is still outstanding and wanting me to provide my credit card details over the phone with the cvv?

To make matters worse, for my holding deposit which was double-charged and has been held by the company for over 4 months after the rental period, they claim to be having technical issues returning into my credit card.

They will never see my business again.