Avis stole money from my account months after returning a courtesy car

Please do not use Avis. This company is **********. I returned a courtesy car arranged for me by my insurance company in August 2020 and all the amounts due to Avis were settled. In December 2020 Avis debited my account for an amount close to R2000 and I am still waiting to receive my money back after numerous attempts to contact them for an explanation and a refund.