Sweet Potato Bread Raw in middle

Bought R700+ worth of items yesterday at new Food *****'s Market William Moffat. Did not keep till slip. Went back today to return the raw in the middle bread in package, with price sticker still on package, not thinking twice that I will have a problem with a refund. Cashier called supervisor who said she will need the till slip? I am not understanding why I could not be refunded, as I almost never keep a till slip when buying perishables. Maybe the nice thing would have been to refund me and draw my attention to their return policy for a possible next time? R24 is not the end of the world. It is the principle behind the matter that pees me off. So I would rather not buy in store baked bread at FLM in future as i might forget to hold on to my till slip, in case I need to return raw in the middle bread again (all the schlepp was not worth it).