Poor customer service from Avis car rental, Paarl

I collected my rental car from Avis car rental in Paarl on 25 February 2021. I paid the deposit and insurance which was approximately just over R2k. I returned the car on full tank on 10 March 2021. To date, the deposit which was meant to be refunded to me within 7-10 working days has still not been paid. Instead Avis continues to debit funds from my bank account without any verbal or written notice. On 10 April 2021 I received an email from Avis warning me to return their rental car. I responded that the car had been returned in March, 2 days before it was even due. The person who had sent the initial email then told me to ignore it. Emails, phone calls yield the same unkept promises. This type of unprofessional conduct is really appalling!