Bad service and issue to refund deposit

I am writing to express my deep dissatisfaction with the service I have received from Europcar regarding my flexi rental experience. The car was returned on 24 June 2024, I received an invoice for an amount of R6375, I enquired via email what the amount is for no response received, I also enquired about the refund of my deposit and I was told that my deposit will be refunded in 4 weeks time. On 15 July 2024 an amount of R5800 was deducted from my bank account, upon enquiring they seemingly don't know why the amount was deducted, so im paying for a car that im no longer renting. I will never use Europcar again!!