SANI car rental Nelspruit

I would like to report SANI car rental *****ulent charges, I rented a car for 4 days 11/08/23 till 14th of August 23. The amount(R6148,95) for that Four days was deducted as agreed and the holding deposit was deducted from my account. Due to family commitments I extended the rental period in one day only which was the 15th August 23, I returned the car with full tank and in good condition. And today the 24th August 23 I see my deposit was deducted close to the amount that I have paid for 4days rental from R7100 holding deposit I was charged R5338,67 for extra one day rental and the petrol bill yet the car was returned with full tank. I’m not happy with the amount they charged me for just extra one day rent I want my deposit back.