overcharged for rental car that was inoperable

Rented a car via Safair website on Christmas day and had a nail in the tyre. No replacements so we took to our destination and they said the would send a replacement car. 2 Days later the replacement came so we had no use of the car for 2 full days and no refund on rental. They overcharged for the fuel and mileage when they sent a replacement but refunded the R250. Still waiting for the rental day refund. Will never book with them again. First and last time a customer.