Poor Customer Service received at Sandcity Jet

On Friday, September 1, 2023, around 13:00, I walked into the Jet at Sandton City to pay up my account. When I arrived at the till point, being helped by a cashier by the name of Khanya, I requested that he take an amount of R300 off my account as that was my monthly instalment. Khanya took an amount of R3541. When I questioned him about this, he was like, No, I took R300. Then, when I got home, I noticed that an amount of R3541 was taken off my account. I then made my way to Sandton City on Saturday, September 2, 2023, around 09:15. When I arrived at Jet, I requested for the store manager. At first, the guy at the till was like, No, there is no manager since the manager is on leave. I asked him why a big store like Jet in Sandton City someone would not have who is an acting manager when a manager is not around. This was when he got on the phone and called a lady by the name of Mvula to come and assist. As Mvula got in, I tried to explain to her what had happened. Mvula started saying I am making this sound like it was her fault; she really seemed uninterested in helping me; all she cared about was how it made her feel and not how this is making me feel. After talking to her, she said she couldn't help me with a refund until I got the statement. What made me very angry was that Mvula didn't know when the credit card machine would clear out; she straight told me that she had no idea. At the end of our conversation, Mvula didn't even take my details to follow up if the amount had cleared out from my side; instead, I was the one taking her details. She didn't even give me an apology for what had happened.i now have to deal with the head office on a mistake made by their cashier. I was told by Mvula that this incident wasn't the first so I am guessing this was supposed to make me feel good right?