Unprofessional Supervisor

I just returned cheese with mold that i bought earlier today from Pick n Pay at Kelvin Village. I was soooo appalled by the attitude of the supervisor Rebecca, it seemed like such incidents are a norm and they never apologise for them. She asked for the slip (no 'please') was used as she requested, i went to fetch another cheese and she asked that i check if its okay before leaving the shop of which i did. As i was leaving i let her know that i feel she treated this situation in a very condescending manner, that she didn't bother to apologise for the inconvenience caused bcz i was very inconvenienced when i had to return back but i didnt even bother going into details. After voicing how i felt, all I got was an 'ohh sorry' as she checked the slip again. Please teach her some customer etiquettes, the experience i received was a disgrace and appalling considering that she's the supervisor and the other staff are always very friendly and helpful.