Bad service

On the 2nd of November I got a curtesy car via my insurance. When the car was delivered I had to pay a holding fee using my cheque card. The lady that delivered the car had a speed point machine to facilitate the transaction. She kept getting an error message and seemed the transaction was reversed each time she put it through. On checking my bank account I noticed that the amount had been deducted twice. I contacted my bank to reserve the one amount but they couldn’t assist as the transactions had not cleared. The lady promised to sort the matter out when she got back to the office. More than a week later this has not been sorted and there’s zero communication coming from Avis. I’m the one who has to keep following up and I keep getting empty promises for this to be resolved. The funds have still not been cleared but I can’t access them as transaction has not been reversed. Can someone please attend to this as a matter of urgency!