Poor customer service

Poor customer service from Woolworths at carnival mall. Manager Boitumelo refused to assist me with exchange. My wife bought the incorrect size for my boxers. I'm a medium she bought extra large. Packaging still not open. She refused to assist me at her own discretion. Very disappointed as I have been a loyal customer for over 14 years. Mistakes happen all the time. Why should I be stuck with boxers I did not open and are not my size. So R300 down the drain. Thanks for all your assistance @Woolworths