Disappointed customer service

I had to write this again today because yesterday my laptop died on me as we experienced power outage. Me and my family have been long customers of Food *****s Market in Westgate Shopping Mall and since we have now relocated to Westonaria we thought we had found our second home in a Lenasia Food *****s Market as it would be a convenient one for my family. So on the 23rd of June we went and bought our fruits and veggies as it is our go to store for specifically those and I decided to buy my daughter a chocolate bar. On our arrival at just before I could open it for my four years old daughter I checked the Expiry date and found that it had been expired for a month, so, I decided to ask my fiance to give them a call first thing in the morning and let them know that they should go check if there are any more in the shelves but she refused because i clearly indicated that she shouldnt cause any drama (women with their drama of course).. so I decided to make a call myself and let them know. I spoke to a lady, told her about my incident and asked if could come in the afternoon as I had to start somewhere and in the mean time they in the shop could remove the rest if there were any others in the shelves.. so I got there around 2 in the afternoon, asked for the lady they referred me to over the phone, I told her about my incident and she called another one.. they took me to the shelves and started checking the rest while interrogating me with questions.. I stood there as they even showed each other that they didn't have any expired ones as if I was making this up .. I looked at them and in my mind I was like I called them in the morning with my airtime, inconvenienced and yet humble so as to experience this foolish behavior they are pulling in front of me.. they asked me if I would want a refund and I said no but I would take a nother one.. but because I was treated at a face value and classified I just took my 20 bucks and left.. I left the store soon disappointed and belittled because why would I drive all the way from where I was since well we reside in the Westonaria just to collect 20 rands when I could have thrown the certain brands bar out the window and buy another one at another store and just call the customer care line and report the matter to them. I was ashamed as my fiance told that they took advantage of you because they know men don't usually make scenes and she was proven right.. they didn't apologize. Even the security guy at the door said something that disturbed me about the possible treatment because of the color of skin.. I must say.. after being a long time customer for Food *****s Market and at the end to get this kind of treatment.. I am very disappointed and very saddened.