Horrible service

So I bought shoes from Adidas south Africa, when I got it I immediately request a return, I got a message saying it will be collected the next day, two weeks later they collected only, now a week after the collection they haven't even scanned the product and refunded Me, they didn't even know that the parcel was collected, now they are asking for a document that was left by the courier, meanwhile I've signed on the portable machine the driver has, they have no idea what is going on in their own business I still up to this day 3 weeks later not received my refundm