Disappointed in Adidas service

I’m very disappointed in Adidas South Africa, I ordered 2 sneakers for my children on the 29th November. No communication was sent regarding delays or shortages of stock ,only after 10 working days after ordering online I get notice of a partial order being shipped and later a message for a refund. I paid R1,019.00 and the email for a refund is R9,17.10 , please tell me why my refund is short because the delivery was free and it is not fault that there is no stock.