Bad service

Last month I took my mom in-law's car for service at Hyundai Polokwane. When I was given invoice to pay, they gave me also quotation for other parts needed for replacement. So when I get to the cashier, I gave him both the quote and invoice but made a mistake and paid the amount on the quotation. They requested that I give them all my details for which they will pay in few days. It is now a month and I received my R487. @Hyundai Polokwane I have been patience enough,please pay my money back.