Terrible account management, overcharging and double charging.

I rented a vehicle from AVIS JHB Loveday on the 2nd of March 2020, and intended to use it until the 31st of March but returned it on the 26th due to the lockdown. Firstly, I received an SMS requesting the latest mileage on the vehicle on the 30th, after I had already returned the vehicle. Secondly, I received an invoice days later that reflected that the vehicle had been returned on the 30th (which would have been impossible as the branch was closed during lockdown) instead of the 26th. Third, a hold on my card for more than double the rental amount was placed on my card AFTER the invoice was generated and was not released for over 2 weeks. Fourth, the hold was eventually released and then the overcharged invoice amount was deducted from my card. The last straw, in the week of the 27th of April I receive another SMS from AVIS requesting a mileage update which I ignore. I receive an SMS on the 30th thanking me for using AVIS and then another hold is placed on my card (of more than double the invoice amount that was already deducted and paid weeks earlier). I believe the next step will be that my card will actually be debited again for the same invoice which is already overstated. I've used AVIS for years but this has been the worst service I've ever received from anywhere ever.