Being ****** as a customer

I’m so disappointed with how I was treated today as a customer. On Friday 25/08/2023 I paid my TFG account R100 and my credit increased to R861.00 on Sunday I saw cargo pants which i like I decided to buy them with a top and the total for both items was R648.50 when I got home the pants couldn’t fit so I went back to Foschini in Sammy marks to exchange the pants they told me that they needed the card I went back home to get the card. When I got back at the store the lady that was assisting me by the name of Dimakatso told me that I had to pay R300 and I asked her why because I’m exchanging the pants I’m not buying them her response was I don’t have enough credit which really surprised me. I then told her that I don’t have any money with me so I can’t pay that amount so she can rather give me back my pants I will so what I can do she then said she can’t because she already refunded the money back into my account, so I was confused by all of this. She said I only have R200 in my account so I need to add R300 so that I can get the pantsuit because it means when I bought the pants I overslept on my account. Your could tell that the ladies were bored because clearly I was wasting their time they wanted to knock they didn’t even try to assist me and find out what exactly happened. The other lady came to me to try and explain but still what they were saying didn’t make sense to me. Firstly I had R861 in my account and I spent R648 which means I’m left with R212 in my account so how can I overspend when I’m left with R212. Secondly when I requested for my pants back they told me that they can’t because the money was refunded back into my account, cool so why do I have R212 in my account when you guys refunded the money back where is the R559 for the pants? Now you want me to buy the pants for the second time. You have my card can’t you check on your system how much I had before buying the items and how much I paid on Friday? I need this to be resolved because I feel I’m being ****** as a customer. Does it really make sense that someone can overspend and still be left with some credit.