Furious customer

I payed for 2 pairs of takkies for my kids on Black Friday and was told delivery was free. While waiting for the takkies to be delivered they sent a message saying delivery is NO more free and I must pay an extra R500 for delivery which I didnt have. I requested them to cancel my order and reimburse my money which he agreed to but said it would take 15 working days. 15 days has passed and still no money. I am going to the police station today to open a case against them as I worked hard for that R1900.