Terms and conditions not clear for customers

Disgusting service at markams Markpark vereeniging from the so called manager. She told us that she's doing us a favor with exchange/refund whereas she can't provide it in writing I even asked her to show me cause at the back of the receipts there's terms and conditions and accessories is not included as part of the things that can't be exchanged. She even went to an extent of saying we must go back to the store where we bought the item. I need answers from markams why other exchange policy are not at the back of receipt but only known by managers who are even failing providing in black and white I need it in writing